How to Integrate a .JSON text array into the program?

I'm trying to create a multiple choice trivia game which selects random questions from an offline database (think Quizoid) and displays it on a panel/image. Also I'm absolutely new to Unity and most of the tutorials and forums go right over my head. Here is a sample from the .json file:

 {
     "quiz":[
         {
             "index":"1",
             "category":"Geography",
             "question":"What is the capital of Tunisia?",
             "answer":[{
                 "1":"Tunis",
                 "2":"Ulan Bator",
                 "3":"Prague",
                 "4":"Limpopo"
                 }],
         },
     
         {
             "index":"2",
             "category":"Science",
             "question":"Which chemical element is represented by Dy?",
             "answer":[{
                 "1":"Dysprosium",
                 "2":"Darmstadtium",
                 "3":"Dubnium",
                 "4":"Dungsten"
                 }],
         },
 
         {
             "index":"3",
             "category":"History",
             "question":"Which animal was famously utilized by Hannibal in his battles?",
             "answer":[{
                 "1":"Elephants",
                 "2":"Tigers",
                 "3":"Wolves",
                 "4":"Eagles"
                 }],
         },
          ]
 }

I've tried this:`

 void Start()
       {
           jsonString = File.ReadAllText(Application.dataPath + "/StreamingAssets/questions.json");
           itemData = JsonMapper.ToObject(jsonString);
 
           Debug.Log(itemData["quiz"][34]["question"]);
 
       }           

but it usually gives this error : "KeyNotFoundException: The given key was not present in the dictionary." I've tried : https://www.youtube.com/watch?v=bGrTN4670cY https://www.youtube.com/watch?v=OyQQ-7-22Hw

Is it that i got the coding wrong or should I just use sqlite/xml? Any help is greatly appreciated