use proconio::*;

fn main() {
	input! {
		t: usize,
	}
	
	for _ in 0..t {
		input! {
			n: usize,
			k: usize,
			mut a: [usize; n],
		}
		
		let mut ans: usize = 1;
		a.sort();
		if let Some(va) = a.first_mut() { *va -= k; }
		a.iter().for_each(|i| ans *= i);
		println!("{ans}");
	}
}