#include <bits/stdc++.h>

using namespace std;

const int MaxN = (int)5e3 + 10;
const int INF = (int)1e9;
const int MOD = (int)1e9 + 7;

int cnk[MaxN][MaxN];
int n, k, a[MaxN];

int mPow(int a, int n) {
	int r = 1;
	while (n > 0) {
		if (n & 1) {
			r = 1LL * r * a % MOD;
		}
		a = 1LL * a * a % MOD;
		n /= 2;
	}
	return r;
}

void solve() {
	scanf("%d%d", &n, &k);
	assert (1 <= n && n <= 5000);
	assert (1 <= k && k <= n);
	for (int i = 1; i <= n; ++i) {
		scanf("%d", &a[i]);
	}
	int ans = 1;
	if (k <= 2) {
		printf("0\n");
		return;
	}
	sort(a + 1, a + n + 1);
	for (int i = 2; i + 1 <= n; ++i) {
		int cnt = 0;
		for (int l = 1; l <= i - 1; ++l) {
			int r = k - l - 1;
			if (r <= 0) {
				continue;
			}
			cnt = (cnt + 1LL * cnk[i - 1][l] * cnk[n - i][r]) % (MOD - 1);
		}
		ans = 1LL * ans * mPow(a[i], cnt) % MOD;
	}
	printf("%d\n", ans);
}

int main() {
//	freopen("input.txt", "r", stdin);
	for (int i = 0; i < MaxN; ++i) {
		cnk[i][0] = 1;
		for (int j = 1; j <= i; ++j) {
			cnk[i][j] = (cnk[i - 1][j - 1] + cnk[i - 1][j]) % (MOD - 1);
		}
	}
	int t;
	scanf("%d", &t);
	assert (1 <= t && t <= 10);
	while (t --> 0) {
		solve();
	}
	return 0;
}