Object Reference not set to an Instance

 using UnityEngine;
 using System.Collections;
 
 public class QuestionClass2 : MonoBehaviour 
 {
     public Question[] arrayOfQuestions;
     public Question currentQuestion;
     public bool showQuestion = true;
     private int coinToss;
     public bool Heads;
     public 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;
         
         public int correctAnswerIndex;
         
         private int questionWidth = 300;
         private int answerWidth = 75;
         private int questionHeight = 1000;
         private int correctWidth = 500;
         
         public int selectedAnswer = -1;
         
 
           void Update()
     {    
         //currentQuestion.selectedAnswer = 0;
         
         if(currentQuestion.selectedAnswer == currentQuestion.correctAnswerIndex)                  
     >>>>>>>>> getting an error here{
             ChooseRandomQuestion(); // Picks a random question
         }
     }
 }

Ive attached a script to a empty gameobject, Do i need reference that gameobject ?