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




void solve() {
int n , k ; cin >>  n >> k;

vector<int>arr(n);

for(auto &a : arr) cin >>a;


sort(arr.begin() , arr.end());

arr[0] -= k;

cout<<accumulate(arr.begin() , arr.end() ,1LL,  multiplies<long long>());



}

signed main() {

    int t = 1;
    cin >> t;
    while (t--) {
        solve();
        cout<<endl;
    }
    return 0;
}