Quiz Game - Repeating all wrong answered questions

Hey there,

this is my first thread I hope I won't miss anything. I'm a Unity and C# beginner and currently I'm trying to develop a Quiz Game. For test purposes there are only 2 questions stored in a json File. I want to repeat the wrong answered questions. They should be displayed after the last question of a list, but I just cant find a proper way to do that. So far I could manage to display the questions but when answering the last wrong answered question I get the error: "Index was out of range. Must be non-negative and less than the size of the collection."
I would be grateful for any help

Code (CSharp):

1.  
2.    
3.     private void ShowQuestion()
4.     {
5.         RemoveAnswerButtons();
6.  
7.         poolList = new List<Question_Script>(questionPool);
8.         Question_Script questionData = poolList[questionIndex];
9.         questionDisplayText.text = questionData.question;
10.  
11.         for (int i = 0; i < questionData.answers.Length; i++)
12.         {
13.             GameObject answerButtonGameObject = answerButtonObjectPool.GetObject();
14.             answerButtonGameObjects.Add(answerButtonGameObject);
15.             answerButtonGameObject.transform.SetParent(answerButtonParent);
16.  
17.             AnswerButton_Script answerButton = answerButtonGameObject.GetComponent<AnswerButton_Script>();
18.             answerButton.Setup(questionData.answers[i]);
19.         }
20.     }
21.  
22.     private void Show()
23.     {
24.         RemoveAnswerButtons();
25.  
26.         questionDisplayText.text = fbF.question;
27.  
28.         for (int i = 0; i < fbF.answers.Length; i++)
29.         {
30.             GameObject answerButtonGameObject = answerButtonObjectPool.GetObject();
31.             answerButtonGameObjects.Add(answerButtonGameObject);
32.             answerButtonGameObject.transform.SetParent(answerButtonParent);
33.  
34.             AnswerButton_Script answerButton = answerButtonGameObject.GetComponent<AnswerButton_Script>();
35.             answerButton.Setup(fbF.answers[i]);
36.         }
37.     }
38.  
39.     private void RemoveAnswerButtons()
40.     {
41.         while(answerButtonGameObjects.Count> 0)
42.         {
43.             answerButtonObjectPool.ReturnObject(answerButtonGameObjects[0]);
44.             answerButtonGameObjects.RemoveAt(0);
45.         }
46.     }
47.  
48.     public void AnswerButtonClicked(bool correct)
49.     {
50.         if (correct)
51.         {
52.             playerScore += currentRoundData.addScore;
53.             scoreDisplayText.text = "Score" + playerScore.ToString();
54.             poolList.RemoveAt(0);
55.         }
56.  
57.         else
58.         {
59.             allfbF.Add(poolList[questionIndex]);
60.             poolList.RemoveAt(0);
61.         }
62.  
63.         if (poolList.Count > questionIndex)
64.         {
65.             questionIndex++;
66.             ShowQuestion();
67.          }
68.  
69.         else
70.         {
71.             if (allfbF.Count > 0 && poolList.Count <= questionIndex)
72.             {
73.                 Show();
74.                 if (allfbF.Count > fbFIndex)
75.                 {
76.                     if (correct)
77.                     {
78.                         allfbF.RemoveAt(0);
79.                         fbFIndex++;
80.                     }
81.                 }
82.                 else
83.                 {
84.                     EndRound();
85.                 }
86.             }
87.         }
88.     }
89.