#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;

using mint = atcoder::modint998244353;

mint exp_all(int n) {
    mint e = 0;
    for (int i = 1; i <= n; i++) {
        e += mint(n) / i;
    }
    return e;
}

void solve() {
    int N, L;
    cin >> N >> L;

    set<int> D;
    for (int i = 0; i < N; i++) {
        int d;
        cin >> d;
        D.insert(d);
    }

    if (L % 2 == 1) {
        cout << exp_all(N).val() << "\n";
        return;
    }

    int diameters = 0, normals = 0;
    for (int d: D) {
        int opposition = (d + L / 2) % L;
        D.contains(opposition) ? diameters++ : normals++;
    }
    diameters /= 2;

    if (diameters <= 1) {
        cout << exp_all(N).val() << "\n";
        return;
    }

    vector dp(3, vector(diameters + 1, vector<mint>(normals + 1, 0)));

    for (int i = 1; i >= 0; i--) {
        for (int j = diameters; j >= 0; j--) {
            for (int k = normals; k >= 0; k--) {
                mint remain = N - i - j - k;
                dp[i][j][k] = mint(i + j + k) / remain;

                if (i < j) {
                    dp[i][j][k] += (dp[i + 1][j][k] + 1) * (j - i) / remain;
                }
                if (j < diameters) {
                    dp[i][j][k] += (dp[i][j + 1][k] + 1) * 2 * (diameters - j) / remain;
                }
                if (k < normals) {
                    dp[i][j][k] += (dp[i][j][k + 1] + 1) * (normals - k) / remain;
                }
            }
        }
    }

    cout << dp[0][0][0].val() << "\n";
}

int main() {
    int T;
    cin >> T;

    while (T--) solve();
}