How am I Randomize my id in json file.

Please help me on how i randomize the id of my questions in json file. What part of this code can I put the code for the random.

here is my code:

using UnityEngine; using System.Collections; using LitJson; using UnityEngine.UI; using System.IO;

public class Question : MonoBehaviour {

 public string  filePath;
 public string jsonString;
 public JsonData questionData;
 public int numberQuestion=0;
 public GameObject answerPrefab;
 public bool nextQuestion;
 public bool clickAnswer;
 public int score;

 public void QuestionBegin(string jsonName){
     score = 0;
     nextQuestion = true;
     //filePath = (Application.dataPath + jsonName);
     //TextAsset file = Resources.Load(filePath) as TextAsset;
     //Debug.Log (file);
     //jsonString = file.ToString ();
     //jsonString = File.ReadAllText(jsonName);
     filePath = System.IO.Path.Combine (Application.streamingAssetsPath, jsonName + ".json");
     StartCoroutine ("Json");
     questionData = JsonMapper.ToObject(jsonString);
     OnClick ();


 }

 IEnumerator Json(){
     if (filePath.Contains ("://")) {
         WWW www = new WWW (filePath);
         yield return www;
         jsonString = www.text;
     }

     else{
         
         jsonString = System.IO.File.ReadAllText (filePath);

     }


 }

 public void OnClick (){
     if(numberQuestion >= questionData["data"].Count){
          
         Debug.Log ("Result of");

         if (score == questionData ["data"].Count) {
             GameObject.Find ("RankMessage").GetComponent<Text> ().text = "VERY GOOD";
         }else
             if (score >= questionData ["data"].Count*1/2) {
                 GameObject.Find ("RankMessage").GetComponent<Text> ().text = "GOOD";
         }else
             if (score <= questionData ["data"].Count*1/2) {
                 GameObject.Find ("RankMessage").GetComponent<Text> ().text = "FAILED";
             }
         
         MenuManager menuResult = GameObject.Find("Canvas").GetComponent<MenuManager>();
         menuResult.ShowMenu (GameObject.Find("Result").GetComponent<Menu>());

         GameObject.Find ("Score").GetComponent<Text> ().text = score.ToString () + "/" + questionData ["data"].Count;
     }


     if (nextQuestion) { 

     GameObject[] answerDestroy = GameObject.FindGameObjectsWithTag("Answer");
     if (answerDestroy != null) {
         for (int x = 0; x < answerDestroy.Length; x++) {
             DestroyImmediate (answerDestroy [x]);
         }
     }

     GameObject.Find ("ShortQuiz1/Panel/QuestionContent/Question").GetComponentInChildren<Text> ().text = questionData ["data"] [numberQuestion] ["question"].ToString ();
     
     
     for (int i = 0 ; i < questionData ["data"] [numberQuestion] ["answer"].Count; i++) {

         GameObject answer = Instantiate (answerPrefab);
         answer.GetComponentInChildren<Text> ().text = questionData ["data"] [numberQuestion] ["answer"] [i].ToString ();
         Transform answerContent = GameObject.Find ("AnswerContent").GetComponent<Transform> ();
         answer.transform.SetParent (answerContent);

         string x = i.ToString ();

         if (i == 0) {
             answer.name = "Correct Answer";
             answer.GetComponent<Button> ().onClick.AddListener (() => Answer ("0"));
         } else {
             answer.name = "Wrong Answer" + x;
             answer.GetComponent<Button> ().onClick.AddListener (() => Answer (x)); 
         }
         answer.transform.SetSiblingIndex (Random.Range (0, 3));

     }

     numberQuestion++;
     nextQuestion = false;
     clickAnswer = true;
     StartCoroutine ("Timer");
 }
     

}

 public void Answer(string x){
     
     if (clickAnswer) {
         if (x == "0") {
             score++;
             GameObject.Find ("Correct Answer").GetComponent<Button> ().image.color = Color.green;
             GameObject.Find ("Image (" + numberQuestion + ")").GetComponent<Image> ().color = Color.green;
             Debug.Log ("Correct Answer");
         } else {
             GameObject.Find ("Wrong Answer" + x).GetComponent<Button> ().image.color = Color.red;
             GameObject.Find ("Correct Answer").GetComponent<Button> ().image.color = Color.green;
             GameObject.Find ("Image (" + numberQuestion + ")").GetComponent<Image> ().color = Color.red;
             Debug.Log ("Wrong Answer");
         }
     }
         nextQuestion = true;
         clickAnswer = false;
 }

     IEnumerator Timer(){
     Image time = GameObject.Find ("Timer").GetComponent<Image>();
     time.fillAmount = 1; 
     float timeToWait = 5f;
     float incrementToRemove = 0.05f;
     float x = time.fillAmount / timeToWait * incrementToRemove;

     while (timeToWait > 0) {
         yield return new WaitForSeconds (incrementToRemove);

         if (!nextQuestion) {
             time.fillAmount -= x;
             timeToWait -= incrementToRemove;
         }else{
             timeToWait = 0;
             
     }

     if(time.fillAmount <= 0.01f){
         
         for(int i=1; i<4; i++){
             
             GameObject.Find ("Wrong Answer" + i ).GetComponent<Button> ().image.color = Color.red;
         }
         GameObject.Find ("Correct Answer").GetComponent<Button> ().image.color = Color.green;
         GameObject.Find ("Image (" + numberQuestion + ")").GetComponent<Image> ().color = Color.red;
         clickAnswer = false;
         nextQuestion = true;
     }

         
     }


 }

}

thank you! :)