unity sets random options, continues if it encounters a repeat, and gets stuck in an infinite loop

unity sets random options, if encountered repeated continue, stuck in an infinite loop. If you set the number of loops to less than 1, the loop can proceed, but the last option is not assigned.

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;

public class Answer_Ti : MonoBehaviour
{
    //读取文档
    string[][] ArrayX;
    string[] lineArray;
    public int topicMax = 3;//最大题数
    private List<bool> isAnserList = new List<bool>();//存放是否答过题的状态
    //加载题目
    public Text TM_Text;
    public Button[] Buttonlist;//答题Button
    public Text indexText;//当前第几题
    public List<Text> DA_TextList;//选项
    private int topicIndex = 0;//第几题
    public Text tipsText;//提示信息
    public List<int> Qarray;//存放现有题目数组
    public int CorNum=0;//正确题数
    public static Answer_Ti instance;
    void Start()
    {
        TextCsv();
        LoadAnswer();
        instance = this;
        
    }


    /*****************读取txt数据******************/
    void TextCsv()
    {
        //读取csv二进制文件  
        TextAsset binAsset = Resources.Load("XuanZe", typeof(TextAsset)) as TextAsset;
        //读取每一行的内容  
        lineArray = binAsset.text.Split('\r');
        //创建二维数组  
        ArrayX = new string[lineArray.Length][];
        //把csv中的数据储存在二维数组中  
        for (int i = 0; i < lineArray.Length; i++)
        {
            ArrayX[i] = lineArray[i].Split(':');
        }
        //查看保存的题目数据
        for (int i = 0; i < ArrayX.Length; i++)
        {
            for (int j = 0; j < ArrayX[i].Length; j++)
            {
                Debug.Log(ArrayX[i][j]);
            }
        }


    }
    /*****************加载题目******************/
    public void LoadAnswer()
    {

        indexText.text = "第" + (topicIndex + 1) + "题：";//第几题            
        //随机抽一句诗
        int n = RandomQ();
        TM_Text.text = ArrayX[n][0];
        //加载选项
        //设置正确选项
        int flag = Random.Range(0, 4);
        Debug.Log(flag);
        Buttonlist[flag].onClick.AddListener(Correct);
        Buttonlist[flag].GetComponentInChildren<Text>().text = ArrayX[n][1];
        //设置错误选项
        int y = 0;
        while (y<=3)//这个设置成2则可以循环，但最后一个选项没有赋值
        {
            int l = 1;
            if (y != flag)
            {

                int j = Random.Range(2, 4);
                //如果重复则break
                for (int i = 0; i < y; i++)
                {
                    if (ArrayX[n][j] == Buttonlist[i].GetComponentInChildren<Text>().text)
                    {
                        l=0;
                    }

                }
                if(l==0)
                  continue;
                Buttonlist[y].onClick.AddListener(() => Wrong(Buttonlist[flag].GetComponentInChildren<Text>().text));
                Buttonlist[y].GetComponentInChildren<Text>().text = ArrayX[n][j];
                y++;
                Debug.Log(y);
            }
            else
            {
                y++;
                Debug.Log(y);
            }
        }
    }
    public void Correct()
    {
        tipsText.text = "恭喜您，回答正确！";
        CorNum++;
    }
    public void Wrong(string s)
    {
        tipsText.text = "很遗憾，正确选项为"+"“"+s+"”";
    }
    public bool AlreadyQ(int n)
    {
        for(int i = 0;i<Qarray.ToArray().Length;i++)
        {
            if(n==Qarray[i])
            {
                return true;
            }
        }
        return false;
    }
    //下一题
    public void NextQ()
    {
        if(topicIndex < topicMax)
        {
            TM_Text.text ="";
            tipsText.text = "";
            LoadAnswer();
            Debug.Log(topicIndex);
            topicIndex++;
        }
        else
        {
            UnityEngine.SceneManagement.SceneManager.LoadScene(4);
        }

    }
    //随机抽一句诗
    public int RandomQ()
    {
        while(true)
        {
            int n = Random.Range(0,lineArray.Length);
            if(topicIndex == 0)
            {
                Qarray.Add(n);
                return n;
            }
            else if(!AlreadyQ(n))
            {
                Qarray.Add(n);
                return n;
            }
        }
    }

}