#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <algorithm>
#include <atcoder/all>
#include <bitset>
#include <cassert>
#include <cmath>
#include <ctime>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <stack>
#include <string>
#include <tuple>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n)-1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int, int>
#define pil pair<int, ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int, int>>
#define vpll vector<pair<ll, ll>>
#define vvpii vector<vector<pair<int, int>>>
#define vvpll vector<vector<pair<ll, ll>>>

using mint = modint998244353;

template <typename T>
void debug(T e) {
    cerr << e << endl;
}

template <typename T>
void debug(vector<T> &v) {
    rep(i, v.size()) { cerr << v[i] << " "; }
    cerr << endl;
}

template <typename T>
void debug(vector<vector<T>> &v) {
    rep(i, v.size()) {
        rep(j, v[i].size()) { cerr << v[i][j] << " "; }
        cerr << endl;
    }
}

template <typename T>
void debug(vector<pair<T, T>> &v) {
    rep(i, v.size()) { cerr << v[i].first << " " << v[i].second << endl; }
}

template <typename T>
void debug(set<T> &st) {
    for (auto itr = st.begin(); itr != st.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(multiset<T> &ms) {
    for (auto itr = ms.begin(); itr != ms.end(); itr++) {
        cerr << *itr << " ";
    }
    cerr << endl;
}

template <typename T>
void debug(map<T, T> &mp) {
    for (auto itr = mp.begin(); itr != mp.end(); itr++) {
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out() { cerr << endl; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << H << " ";
    debug_out(T...);
}

ll my_pow(ll x, ll n, ll mod) {
    // 　繰り返し二乗法．x^nをmodで割った余り．
    ll ret;
    if (n == 0) {
        ret = 1;
    } else if (n % 2 == 1) {
        ret = (x * my_pow((x * x) % mod, n / 2, mod)) % mod;
    } else {
        ret = my_pow((x * x) % mod, n / 2, mod);
    }
    return ret;
}

ll inv(ll x, ll mod) { return my_pow(x, mod - 2, mod); }

int main() {
    ll T;
    cin >> T;
    while (T--) {
        ll N, M, L, R;
        cin >> N >> M >> L >> R;
        ll ans = (R - L + 1) % mod2;
        // 非負のときの 0 以上 R 以下の個数
        ll div_r = R / (N - 1);
        ll rem_r = R % (N - 1);
        // debug_out(div_r, rem_r);
        ans = (ans + (((rem_r + 1) % mod2) * (div_r % mod2)) % mod2) % mod2;
        if (div_r >= 1) {
            ll times = ((div_r % mod2) * ((div_r - 1) % mod2)) % mod2;
            times = (times * inv(2LL, mod2)) % mod2;
            times = (times * (N - 1)) % mod2;
            ans = (ans + times) % mod2;
        }

        if (L >= 1) {
            ll div_l = (L - 1) / (N - 1);
            ll rem_l = (L - 1) % (N - 1);
            ans =
                (ans + mod2 - (((rem_l + 1) % mod2) * (div_l % mod2)) % mod2) %
                mod2;
            if (div_l >= 1) {
                ll times = ((div_l % mod2) * ((div_l - 1) % mod2)) % mod2;
                times = (times * inv(2LL, mod2)) % mod2;
                ans = (ans + mod2 - times) % mod2;
            }
        }
        // cout << ans << endl;

        ll tmp = L;
        L = M - R;
        R = M - tmp;
        // debug_out(L, R);
        // 負のときも同じことを繰り返す
        div_r = R / (N - 1);
        rem_r = R % (N - 1);
        // debug_out(div_r, rem_r);
        ans = (ans + (((rem_r + 1) % mod2) * (div_r % mod2)) % mod2) % mod2;
        if (div_r >= 1) {
            ll times = ((div_r % mod2) * ((div_r - 1) % mod2)) % mod2;
            times = (times * inv(2LL, mod2)) % mod2;
            times = (times * (N - 1)) % mod2;
            ans = (ans + times) % mod2;
        }
        // cout << ans << endl;

        if (L >= 1) {
            ll div_l = (L - 1) / (N - 1);
            ll rem_l = (L - 1) % (N - 1);
            ans =
                (ans + mod2 - (((rem_l + 1) % mod2) * (div_l % mod2)) % mod2) %
                mod2;
            if (div_l >= 1) {
                ll times = ((div_l % mod2) * ((div_l - 1) % mod2)) % mod2;
                times = (times * inv(2LL, mod2)) % mod2;
                ans = (ans + mod2 - times) % mod2;
            }
        }
        cout << ans << endl;
    }
}