#include <bits/stdc++.h>
#ifdef LOCAL
#include <debug.hpp>
#else
#define debug(...) void(0)
#endif

#include "atcoder/modint"

using namespace std;

typedef long long ll;
#define all(x) begin(x), end(x)
constexpr int INF = (1 << 30) - 1;
constexpr long long IINF = (1LL << 60) - 1;
constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};

template <class T> istream& operator>>(istream& is, vector<T>& v) {
    for (auto& x : v) is >> x;
    return is;
}

template <class T> ostream& operator<<(ostream& os, const vector<T>& v) {
    auto sep = "";
    for (const auto& x : v) os << exchange(sep, " ") << x;
    return os;
}

template <class T, class U = T> bool chmin(T& x, U&& y) { return y < x and (x = forward<U>(y), true); }

template <class T, class U = T> bool chmax(T& x, U&& y) { return x < y and (x = forward<U>(y), true); }

template <class T> void mkuni(vector<T>& v) {
    sort(begin(v), end(v));
    v.erase(unique(begin(v), end(v)), end(v));
}

template <class T> int lwb(const vector<T>& v, const T& x) { return lower_bound(begin(v), end(v), x) - begin(v); }

using mint = atcoder::modint998244353;

template <class T> T ceil(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? (x + y - 1) / y : x / y);
}
template <class T> T floor(T x, T y) {
    assert(y >= 1);
    return (x > 0 ? x / y : (x - y + 1) / y);
}

void solve() {
    ll N, M, L, R;
    cin >> N >> M >> L >> R;

    mint ans = R - L + 1;
    for (int _ = 0; _ < 2; _++) {
        if (L / (N - 1) == R / (N - 1))
            ans += mint(R - L + 1) * (L / (N - 1));
        else {
            ll l = ceil(L, N - 1) * (N - 1);
            ans += mint(l - L) * (L / (N - 1));
            ll r = floor(R, N - 1) * (N - 1);
            ll LL = l / (N - 1), RR = r / (N - 1) - 1;
            if (LL <= RR) ans += mint(LL + RR) * (RR - LL + 1) / 2 * (N - 1);
            ans += mint(R - r + 1) * (R / (N - 1));
        }
        L = M - L, R = M - R;
        swap(L, R);
    }

    cout << ans.val() << '\n';
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int T;
    cin >> T;
    for (; T--;) solve();
    return 0;
}