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

const int N = 30000005;
const int P = 998244353;

#define ll long long
#define ld long double


int fac[N], ifac[N];
inline int qpow(int a, int b = P - 2) {
    int res = 1;
    while (b) {
        if (b & 1) res = 1ull * res * a % P;
        a = 1ull * a * a % P;
        b >>= 1;
    }
    return res;
}
inline void init(int n) {
    fac[0] = 1;
    for (int i = 1; i <= n; i++) fac[i] = 1ull * fac[i - 1] * i % P;
    ifac[n] = qpow(fac[n]);
    for (int i = n - 1; i >= 0; i--) ifac[i] = 1ull * ifac[i + 1] * (i + 1) % P;
}
inline int binom(int n, int m) {
    return 1ll * fac[n] * ifac[m] % P * ifac[n - m] % P;

}

int main() {
    init(3e7);
    int T; scanf("%d", &T);
    while (T--) {
        int n, m, r, s;
        scanf("%d%d%d%d", &n, &m, &r, &s);
        int ans = binom(n * m + s + r + n, n);
        ans = 1ll * (r + s) * ans % P * qpow(n * m + s + r + n) % P;
        printf("%d\n", ans);
    }
    return 0;
}