using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Globalization;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics.X86;
using System.Runtime.Intrinsics.Arm;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new long[t];
        for (var u = 0; u < t; ++u)
        {
            var c = NList;
            var a = NList;
            ans[u] = Rect(c[0], c[1], a);
        }
        WriteLine(string.Join("\n", ans));
    }
    static long Rect(int n, int l, int[] a)
    {
        if (l % 2 == 1) return Gacha(n);
        var set = new HashSet<int>();
        foreach (var ai in a) if (ai >= l / 2) set.Add(ai);
        var count = 0;
        foreach (var ai in a) if (ai < l / 2 && set.Contains(ai + l / 2)) ++count;
        if (count < 2) return Gacha(n);
        return Gacha2(n, count);
    }
    static int mod = 998_244_353;
    static long Gacha(int n)
    {
        var dp = new long[n + 1];
        for (var i = n - 1; i >= 0; --i)
        {
            dp[i] = (dp[i + 1] + n * Exp(n - i, mod - 2, mod) % mod) % mod;
        }
        return dp[0];
    }
    static long Gacha2(int n, int p)
    {
        var dp1 = new long[p + 1];
        dp1[p - 1] = n * Exp(p - 1, mod - 2, mod);
        for (var i = p - 2; i >= 0; --i)
        {
            var rev2ni = Exp(2 * p - i - 2, mod - 2, mod);
            dp1[i] = (2 * (p - i - 1) * dp1[i + 1] + n) % mod * rev2ni % mod;
        }
        var dp0 = new long[p + 1];
        dp0[p] = (dp1[p - 1] + n * Exp(p, mod - 2, mod)) % mod;
        for (var i = p - 1; i >= 0; --i)
        {
            var rev2ni = Exp(2 * p - i, mod - 2, mod);
            dp0[i] = (i * (i == 0 ? 0 : dp1[i - 1]) + 2 * (p - i) * dp0[i + 1] + n) % mod * rev2ni % mod;
        }
        return dp0[0];
    }
    static long Exp(long n, long p, int mod)
    {
        long _n = n % mod;
        var _p = p;
        var result = 1L;
        if ((_p & 1) == 1) result *= _n;
        while (_p > 0)
        {
            _n = _n * _n % mod;
            _p >>= 1;
            if ((_p & 1) == 1) result = result * _n % mod;
        }
        return result;
    }
}