A

#include <bits/stdc++.h>
using namespace std;
int main() {
    int q ;
    cin >> q ;
    while(q--) {
        int a,b,x,y ;
        cin >> a >> b >> x >> y ;
        x = x+1 ;
        y = y+1 ;
        vector <int> vec ;
        vec.push_back((a-x)*(b));
        vec.push_back((x-1)*b);
        vec.push_back(a*(y-1));
        vec.push_back(a*(b-y));
        sort(vec.begin(),vec.end(),greater<int>());
        cout << vec[0] << endl;
    }
    return 0 ;
}