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

typedef long long ll;
const ll mod=998244353;
const ll maxn=20000000;

inline ll ksm(ll a,ll x){
	ll ret=1;
	for (;x;x>>=1,a=a*a%mod) if (x&1) ret=ret*a%mod;
	return ret;	
}
inline ll inv(ll a){
	return ksm(a,mod-2);	
}

int fac[maxn+50];
int ifac[maxn+50];

ll C(ll n,ll m){
	if (m<0 || m>n) return 0;
	return 1LL*fac[n]*ifac[m]%mod*ifac[n-m]%mod;	
}

void prepare(){
	fac[0]=1;
	for (int i=1;i<=maxn;i++) fac[i]=1LL*fac[i-1]*i%mod;
	ifac[maxn]=inv(fac[maxn]);
	for (int i=maxn-1;i>=0;i--) ifac[i]=1LL*ifac[i+1]*(i+1)%mod;	
}

int main(){
	ios_base::sync_with_stdio(false);
	prepare();
	int Tcase=1;
	cin >> Tcase;
	for (;Tcase--;){
		ll n,m,r,s;
		cin >> n >> m >> r >> s;
		ll T=n*(m+1)+r+s;
		ll ans=1LL*C(T,n)*(r+s)%mod*inv(T)%mod;
		cout << ans << "\n";
	}
	return 0;	
}