diff --git a/DCProject.Rmd b/DCProject.Rmd
index 478c2099d2f49a7b15539ddcba75f7fbdead8abd..8f9867a08bbd4b88b6e7669bdd03d7c5a02c5e6c 100644
--- a/DCProject.Rmd
+++ b/DCProject.Rmd
@@ -188,12 +188,14 @@ Es können verschiedene Datenvormate eingelesen werden, z.B CSV, XLSX
     na="NA"
     ```
     
+    
 ```{r letter-c, echo=FALSE}
 question("Jetzt bist du dran! Angenommen du möchtest eine .CSV Datei einlesen die im selben Arbeitsverzeichnis liegt, in der Dezimalzahlen mit einem . getrennt werden und fehlende Werte mit NA ausgefüllt werden sollen. Wie gehst du vor?",
   answer('daten_csv <- read.csv("daten.csv")'),
   answer('daten_csv <- read.csv2(file.choose(), na = "NA")'),
   answer('daten_csv <- read.csv("daten.csv", na = "NA")', correct = TRUE),
-  answer('daten_csv <- read.csv2("daten.csv", na = "NA")')
+  answer('daten_csv <- read.csv2("daten.csv", na = "NA")'),
+  answer('daten_csv <- read.csv2("daten.csv", na = "NA" dec= ".")', correct = TRUE)
 )
 ```
     
@@ -229,6 +231,17 @@ narmtest
 rowSums(narmtest, na.rm = TRUE,)
 ```
 
+```{r letter-d, echo=FALSE}
+question("Jetzt bist du dran! Angenommen du möchtest eine der oben genanten Funktionen verwenden welche probleme kann es geben und wie kannst du sie loesen?",
+  answer('Es koennen leerstellen im Datensatzt sein")', correct = TRUE),
+  answer('Ich muss nichts beachten'),
+  answer('Ich benutzen na.remove'),
+  answer('na.rm als parameter an die Funktion mit uebergeben', correct = TRUE),
+  answer('na.omit() verwenden um eine neuen Datensatz zu erstellen', correct = TRUE),
+  answer('Wenn es Probleme mit den Daten geben sollte kann ich nach dem einlesen nichts mehr machen')
+)
+```
+
 ## Datenanalyse
 
 *Information: Die hier dargestellten Tabellen beinhalten zur Veranschaulichung jeweils nur die ersten 10 Zeilen. Unser Datensatz besteht aus 24 Zeilen.*
diff --git a/DCProject.html b/DCProject.html
index 55e3b76623b90641c5a5e272015c017c5352fef2..50c31f18af814f91d26b8f82864caf96b78d630d 100644
--- a/DCProject.html
+++ b/DCProject.html
@@ -684,6 +684,14 @@ rowMeans()</code></pre>
 </div>
 <pre class="r"><code>rowSums(narmtest, na.rm = TRUE,)</code></pre>
 <pre><code>## [1]  4 15  6</code></pre>
+<div class="panel panel-default tutorial-question-container">
+<div data-label="letter-d" class="tutorial-question panel-body">
+<div id="letter-d-answer_container" class="shiny-html-output"></div>
+<div id="letter-d-message_container" class="shiny-html-output"></div>
+<div id="letter-d-action_button_container" class="shiny-html-output"></div>
+<script>if (Tutorial.triggerMathJax) Tutorial.triggerMathJax()</script>
+</div>
+</div>
 </div>
 </div>
 <div id="section-datenanalyse" class="section level2">
@@ -1113,54 +1121,103 @@ session$onSessionEnded(function() {
 </script>
  
 <script type="application/shiny-prerendered" data-context="server">
-learnr:::question_prerendered_chunk(structure(list(type = "learnr_radio", label = "letter-c", question = structure("Jetzt bist du dran! Angenommen du möchtest eine .CSV Datei einlesen die im selben Arbeitsverzeichnis liegt, in der Dezimalzahlen mit einem . getrennt werden und fehlende Werte mit NA ausgefüllt werden sollen. Wie gehst du vor?", html = TRUE, class = c("html", 
-"character")), answers = list(structure(list(id = "lnr_ans_171b41d", 
-    option = "daten_csv <- read.csv(\"daten.csv\")", value = "daten_csv <- read.csv(\"daten.csv\")", 
-    label = structure("daten_csv &lt;- read.csv(“daten.csv”)", html = TRUE, class = c("html", 
-    "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
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-    label = structure("daten_csv &lt;- read.csv2(file.choose(), na = “NA”)", html = TRUE, class = c("html", 
-    "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
-"tutorial_quiz_answer")), structure(list(id = "lnr_ans_f1ef3b5", 
-    option = "daten_csv <- read.csv(\"daten.csv\", na = \"NA\")", 
-    value = "daten_csv <- read.csv(\"daten.csv\", na = \"NA\")", 
-    label = structure("daten_csv &lt;- read.csv(“daten.csv”, na = “NA”)", html = TRUE, class = c("html", 
-    "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
-"tutorial_quiz_answer")), structure(list(id = "lnr_ans_114e0d3", 
-    option = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\")", 
-    value = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\")", 
-    label = structure("daten_csv &lt;- read.csv2(“daten.csv”, na = “NA”)", html = TRUE, class = c("html", 
-    "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
-"tutorial_quiz_answer"))), button_labels = list(submit = structure("<span data-i18n=\"button.questionsubmit\">Submit Answer<\u002fspan>", html = TRUE, class = c("html", 
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-"character"))), messages = list(correct = structure("Correct!", html = TRUE, class = c("html", 
-"character")), try_again = structure("Incorrect", html = TRUE, class = c("html", 
-"character")), incorrect = structure("Incorrect", html = TRUE, class = c("html", 
-"character")), message = NULL, post_message = NULL), ids = list(
-    answer = "letter-c-answer", question = "letter-c"), loading = NULL, 
-    random_answer_order = FALSE, allow_retry = FALSE, seed = 2009452949.56428, 
-    options = list()), class = c("learnr_radio", "tutorial_question"
+learnr:::question_prerendered_chunk(structure(list(type = "learnr_checkbox", label = "letter-c", 
+    question = structure("Jetzt bist du dran! Angenommen du möchtest eine .CSV Datei einlesen die im selben Arbeitsverzeichnis liegt, in der Dezimalzahlen mit einem . getrennt werden und fehlende Werte mit NA ausgefüllt werden sollen. Wie gehst du vor?", html = TRUE, class = c("html", 
+    "character")), answers = list(structure(list(id = "lnr_ans_2877cf6", 
+        option = "daten_csv <- read.csv(\"daten.csv\")", value = "daten_csv <- read.csv(\"daten.csv\")", 
+        label = structure("daten_csv &lt;- read.csv(“daten.csv”)", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_f9e06f8", 
+        option = "daten_csv <- read.csv2(file.choose(), na = \"NA\")", 
+        value = "daten_csv <- read.csv2(file.choose(), na = \"NA\")", 
+        label = structure("daten_csv &lt;- read.csv2(file.choose(), na = “NA”)", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_3f0ce1b", 
+        option = "daten_csv <- read.csv(\"daten.csv\", na = \"NA\")", 
+        value = "daten_csv <- read.csv(\"daten.csv\", na = \"NA\")", 
+        label = structure("daten_csv &lt;- read.csv(“daten.csv”, na = “NA”)", html = TRUE, class = c("html", 
+        "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_efbb2a2", 
+        option = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\")", 
+        value = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\")", 
+        label = structure("daten_csv &lt;- read.csv2(“daten.csv”, na = “NA”)", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_f85c7e2", 
+        option = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\" dec= \".\")", 
+        value = "daten_csv <- read.csv2(\"daten.csv\", na = \"NA\" dec= \".\")", 
+        label = structure("daten_csv &lt;- read.csv2(“daten.csv”, na = “NA” dec= “.”)", html = TRUE, class = c("html", 
+        "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer"))), button_labels = list(submit = structure("<span data-i18n=\"button.questionsubmit\">Submit Answer<\u002fspan>", html = TRUE, class = c("html", 
+    "character")), try_again = structure("<span data-i18n=\"button.questiontryagain\">Try Again<\u002fspan>", html = TRUE, class = c("html", 
+    "character"))), messages = list(correct = structure("Correct!", html = TRUE, class = c("html", 
+    "character")), try_again = structure("Incorrect. Be sure to select every correct answer.", html = TRUE, class = c("html", 
+    "character")), incorrect = structure("Incorrect", html = TRUE, class = c("html", 
+    "character")), message = NULL, post_message = NULL), ids = list(
+        answer = "letter-c-answer", question = "letter-c"), loading = NULL, 
+    random_answer_order = FALSE, allow_retry = FALSE, seed = 1175380697.95267, 
+    options = list()), class = c("learnr_checkbox", "tutorial_question"
 )), session = session)
 </script>
 
 
+<script type="application/shiny-prerendered" data-context="server">
+learnr:::question_prerendered_chunk(structure(list(type = "learnr_checkbox", label = "letter-d", 
+    question = structure("Jetzt bist du dran! Angenommen du möchtest eine der oben genanten Funktionen verwenden welche probleme kann es geben und wie kannst du sie loesen?", html = TRUE, class = c("html", 
+    "character")), answers = list(structure(list(id = "lnr_ans_69e1b79", 
+        option = "Es koennen leerstellen im Datensatzt sein\")", 
+        value = "Es koennen leerstellen im Datensatzt sein\")", 
+        label = structure("Es koennen leerstellen im Datensatzt sein”)", html = TRUE, class = c("html", 
+        "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_6dc5205", 
+        option = "Ich muss nichts beachten", value = "Ich muss nichts beachten", 
+        label = structure("Ich muss nichts beachten", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_d0fb3b7", 
+        option = "Ich benutzen na.remove", value = "Ich benutzen na.remove", 
+        label = structure("Ich benutzen na.remove", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_29f3317", 
+        option = "na.rm als parameter an die Funktion mit uebergeben", 
+        value = "na.rm als parameter an die Funktion mit uebergeben", 
+        label = structure("na.rm als parameter an die Funktion mit uebergeben", html = TRUE, class = c("html", 
+        "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_e10e535", 
+        option = "na.omit() verwenden um eine neuen Datensatz zu erstellen", 
+        value = "na.omit() verwenden um eine neuen Datensatz zu erstellen", 
+        label = structure("na.omit() verwenden um eine neuen Datensatz zu erstellen", html = TRUE, class = c("html", 
+        "character")), correct = TRUE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer")), structure(list(id = "lnr_ans_2729e6d", 
+        option = "Wenn es Probleme mit den Daten geben sollte kann ich nach dem einlesen nichts mehr machen", 
+        value = "Wenn es Probleme mit den Daten geben sollte kann ich nach dem einlesen nichts mehr machen", 
+        label = structure("Wenn es Probleme mit den Daten geben sollte kann ich nach dem einlesen nichts mehr machen", html = TRUE, class = c("html", 
+        "character")), correct = FALSE, message = NULL, type = "literal"), class = c("tutorial_question_answer", 
+    "tutorial_quiz_answer"))), button_labels = list(submit = structure("<span data-i18n=\"button.questionsubmit\">Submit Answer<\u002fspan>", html = TRUE, class = c("html", 
+    "character")), try_again = structure("<span data-i18n=\"button.questiontryagain\">Try Again<\u002fspan>", html = TRUE, class = c("html", 
+    "character"))), messages = list(correct = structure("Correct!", html = TRUE, class = c("html", 
+    "character")), try_again = structure("Incorrect. Be sure to select every correct answer.", html = TRUE, class = c("html", 
+    "character")), incorrect = structure("Incorrect", html = TRUE, class = c("html", 
+    "character")), message = NULL, post_message = NULL), ids = list(
+        answer = "letter-d-answer", question = "letter-d"), loading = NULL, 
+    random_answer_order = FALSE, allow_retry = FALSE, seed = 669280722.688342, 
+    options = list()), class = c("learnr_checkbox", "tutorial_question"
+)), session = session)
+</script>
+ 
 <script type="application/shiny-prerendered" data-context="server">
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-"character")), answers = list(structure(list(id = "lnr_ans_37ebccb", 
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 "character")), incorrect = structure("Incorrect", html = TRUE, class = c("html", 
 "character")), message = NULL, post_message = NULL), ids = list(
     answer = "letter-b-answer", question = "letter-b"), loading = NULL, 
-    random_answer_order = FALSE, allow_retry = FALSE, seed = 1183554803.94886, 
+    random_answer_order = FALSE, allow_retry = FALSE, seed = 201975246.405948, 
     options = list()), class = c("learnr_radio", "tutorial_question"
 )), session = session)
 </script>
@@ -1183,7 +1240,7 @@ learnr:::question_prerendered_chunk(structure(list(type = "learnr_radio", label
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