Don't Understand Error

Hey guys, I am really confused to why I'm getting this error using UnityEngine; using System.Collections;

 public class QuestionClass2 : MonoBehaviour 
 {
     public Question[] arrayOfQuestions;
     public Question currentQuestion;
     public bool showQuestion = true;
     private int coinToss;
     private bool heads;
     private bool tails;
     
         
     public class Question
     {
         private string questionText;
         private Rect questionRect;
         
         private string[] answers = new string[4];
         private string[] displayAnswers = new string[4];
         private Rect[] answerRects = new Rect[4];
         
         private string correctAnswer;
         private Rect correctRect;
         
         private int correctAnswerIndex;
         
         private int questionWidth = 300;
         private int answerWidth = 75;
         private int questionHeight = 1000;
         private int correctWidth = 500;
         
         private int selectedAnswer = -1;
         
         public Question(Vector2 pos, string q, string a, string b, string c, string d, int correct)
         {
             questionText = q;
             answers[0]      = a;
             answers[1]      = b;
             answers[2]      = c;
             answers[3]      = d;
             
             string st = "ABCD";
             for(int i = 0; i < answers.Length; i++)
             {
                 displayAnswers[i] = st[i] + ": " + answers[i];
             }
             
             correctAnswerIndex = correct;
             correctAnswer = "Correct answer: " + answers[correct];
             
             CalcRects (pos);
         }
         
         void CalcRects(Vector2 pos)
         {
             Rect rect = new Rect();
             rect.x = pos.x;
             rect.y = pos.y;
             rect.width = questionWidth;
             rect.height = questionHeight;
             questionRect =  rect;
             
             rect.x += questionWidth;
             rect.width = answerWidth;
             for (int i = 0; i < answers.Length; i++) 
             {
                 answerRects[i] = rect;
                 rect.x += answerWidth;
             }
             
             rect.width = correctWidth;
             correctRect = rect;
         }
         
         public void DisplayQuestion()
         {
             GUI.Label(questionRect, questionText);
             for (int i = 0; i < answers.Length; i++)
             {
                 GUI.Label(answerRects[i], displayAnswers[i]);
             }
             if (selectedAnswer != -1)
             {
                 GUI.Label(correctRect, correctAnswer);
             }
         }
         
         public void CheckForClick(Vector2 pos) 
         {
             for (int i = 0; i < answers.Length; i++) 
             {
                 if (answerRects[i].Contains(pos)) 
                 {
                     selectedAnswer = i;
                     break;
                 }
             }
         }
     }
     
     void Start()
     {
         
         coinToss = Random.Range(0,2);
         switch(coinToss)
         {
             case 0:
                 heads = true;
                 break;
             case 1:
                 tails = true;
                 break;
         }
         Debug.Log(coinToss);
         arrayOfQuestions = new Question [6];
         arrayOfQuestions[5] = new Question(new Vector2(30,0), "heads or tails?","heads", "tails", "", "", coinToss);   
         
     
         //StartQuestions();
     
         arrayOfQuestions = new Question [5]; // Initalizes an array of "Questions"
         
     }
     
     
     
         void StartQuestions()
     {
         arrayOfQuestions[0] = new Question(new Vector2(30,0),   "How many league titles have Liverpool Won?", "18", "5", "10", "9",0);
         arrayOfQuestions[1] = new Question(new Vector2(30,0),  "Who won the World Cup in 2010?", "Germany", "Italy", "Brazil", "Spain", 3);       
         arrayOfQuestions[2] = new Question(new Vector2(30,0),  "Who is the Manager of Manchester United?", "David Moyes", "Rafa Benitez", "Sir Alex Fergerson", "Brendan Rodgers", 0);       
         arrayOfQuestions[3] = new Question(new Vector2(30,0), "The Bundesliga is a professional association football league in which country?", "Italy", "Germany", "Norway", "Austria", 1); 
         arrayOfQuestions[4] = new Question(new Vector2(30,0), "Which footballer claimed that his hand-ball goal against England in 1986 was ‘The hand of God’?","Diego Maradona ", "Pele", "Wayne Rooney", "Gary Lineker", 0);   
     }
     
     
     void ChooseRandomQuestion()
     {
         currentQuestion = arrayOfQuestions[Random.Range(0, arrayOfQuestions.Length)];
     }
     
     
     void Update()
     {
         if(selectedAnswer == correct)>>> Getting an error here. 
         {
                 ChooseRandomQuestion(); // Picks a random question
         }
     }
     
     void OnGUI()
     {
         Event e = Event.current;
         
         if (e.type == EventType.Repaint)
         {
             currentQuestion.DisplayQuestion(); //Only display the currentQuestion.       
         }
         
         if (e.type == EventType.MouseDown)
         {
             foreach(Question thisQ in arrayOfQuestions)
             {
                 thisQ.CheckForClick(e.mousePosition); // MINI: I didn't change this line, I'm guessing you dont need the for loop here, change it and see if it still works if you want.     
             }
         }
     }
 }

Keep getting an error selectedAnswer does no exist in the current context. the only reason why i think im getting this error is because its in a class already. Not sure how to fix the problem