using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;
using System.Security.Cryptography;
using Microsoft.VisualBasic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    static int[] LList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => int.Parse(ReadLine())).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var t = NN;
        var ans = new long[t];
        for (var u = 0; u < t; ++u)
        {
            var c = NList;
            var (n, k) = (c[0], c[1]);
            var a = NList;
            var max = a.Min();
            for (var i = 0; i < n; ++i)
            {
                if (a[i] == max)
                {
                    a[i] -= k;
                    break;
                }
            }
            ans[u] = 1;
            for (var i = 0; i < n; ++i) ans[u] *= a[i];
        }
        WriteLine(string.Join("\n", ans));
    }    
}