use itertools::Itertools;
use proconio::input;

fn main() {
    input! {
        t: usize,
    }

    let output = (0..t).map(|_| solve()).join("\n");
    println!("{output}");
}

fn solve() -> i64 {
    input! {
        (n, k): (usize, i64),
        mut aa: [i64; n],
    }

    let pos_min = aa.iter().position_min().unwrap();
    aa[pos_min] -= k;
    aa.iter().product()
}