#include <iostream>
#include <math.h>
#include <map>
#include <vector>
#include <stdlib.h>
#include <memory.h>
#include <time.h>
#include <string.h>
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <set>
#include <cassert>

using namespace std;

long long mas[111111];
long long mod = 1e9+7;
long long fact[111111];
long long dd[111111];

long long bin_pow(long long b, long long s) {
    if (s == 0) return 1;
    if (s == 1) return b % mod;
    long long d = bin_pow(b, s/2);
    d = (d * d) % mod;
    if (s % 2 == 1)
        d = (d * b) % mod;
    return d;
}

long long f(int n, long long k) {
    if (n == 0) return 1;
    if (k == 0) return 0;
    if (k == 1) return 1;
    if (n == 1) return k % mod;
    return (dd[n-2] * bin_pow(fact[n-1], mod-2))%mod;
}

int main() {
    ios::sync_with_stdio(0);
    int t;
    cin >> t;
    while (t --> 0) {
    	int n, c;
    	long long k;
    	cin >> n >> c >> k;// c++;
    	for(int i = 1; i <= n; ++i) {
        	cin >> mas[i];
        	mas[i] %= mod;
    	}
    
    	fact[0] = 1;
    	for(int i = 1; i <= c; ++i)
        	fact[i] = (fact[i-1] * i)%mod;
    
    	dd[0] = k % mod;
    	long long K = k % mod;
    	for(int i = 1; i <= c; ++i)
        	dd[i] = (dd[i-1] * (K+i))%mod;
    
    
   	 	long long ans = mas[c];
   	 	for(int i = 1; i < c; ++i) {
        	ans += (mas[c-i] * 1ll * f(i+1, k)) % mod;
        	ans %= mod;
    	}
    	cout << ans << "\n";
    }
    return 0;
}