use proconio::input;
fn main() {
    input! {
        t: usize,
    }
    for _ in 0..t {
        input! {
            n: usize,
            k: usize,
            a: [usize; n]
        }
        let mut res = usize::MAX;
        for i in 0..n {
            let mut pro = 1;
            let mut b = a.clone();
            b[i] = a[i] - k;
            for j in 0..n {
                pro *= b[j];
            }
            res = res.min(pro);
        }
        println!("{}", res);
    }
}