#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef vector<int> vi;
typedef vector<long long> vl;
typedef vector<vector<int>> vvi;
typedef vector<vector<long long>> vvl;
typedef pair<int,int> P;
typedef long double ld;

using mint = modint998244353;

mint calc(ll n, ll m, ll x){
	m++; x++;
	ll p = m / (n - 1), q = m % (n - 1);
	ll a = x / (n - 1), b = x % (n - 1);
	mint loop = mint(p) * (n - 1) + mint(q);
	mint res = loop * a + mint(p) * (b) + mint(min(q, b));
	return res;
}

void solve(){
	ll n, m, l, r;
	cin >> n >> m >> l >> r;
//	rep(i, m + 1) cout << calc(n, m, i).val() << "\n";
	cout << (calc(n, m, r) - calc(n, m, l - 1)).val() << "\n";
}

int main(){
	int t;
	cin >> t;
	rep(i, t) solve();
	return 0;
}