Firebase Quizz Question and options Kotlin

I have problem with my quizz app. I create list of question and i want add optionA, optionB and OptionC to my app from firebase.

This is my code:

  private fun getQuestions() {

    FirebaseFirestore.getInstance().collection("userData").get().addOnSuccessListener {result ->
        var count = 1
        var questionList = arrayListOf<String>()
        var optionListA = arrayListOf<String>()
        
        for (document in result) {
            val question = document.getString("question")
            questionList.add(question!!)
        }
      
       for (document in result) {
            val optionA = document.getString("optionA")
            optionListA.add(optionA!!)
        }


        tv_question.text = questionList(0)
        tvOptionOne.text = optionListA(0)

        btn_submit.setOnClickListener {
            tv_question.text = questionList(count++).toString()
            tvOptionOne.text = optionListA(count++).toString()

        }
    }
}

}

I have error after two click
Process: com.example.myapplication, PID: 31340
java.lang.IndexOutOfBoundsException: Index: 4, Size: 4

What i do:

When user click button then change questions and options from my firebase firestore. Questions change good but don’t work with options. Thanks for tips