1315A - Dead Pixel

using namespace std;
int main(void)
{
    int t;
    cin >> t;
    while (t--)
    {
        int a, b, x, y;
        cin >> a >> b >> x >> y;
        int ans = max({x * b, a * y, (a - x - 1) * b, a * (b - y - 1)});
        cout << ans << endl;
    }
    return 0;
}