/* Problem URL: https://codeforces.com/contest/2131/problem/G */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t;
    cin >> t;
    while (t--) {
        int n;
        ll k;
        cin >> n >> k;

        vl fds(n);
        cin >> fds;

        sortv(fds);

        ll mod = 1e9 + 7;

        auto fastpow = [&](ll a, ll p) {
            ll ans = 1;
            ll now = a;

            rep(i, 30) {
                if ((p >> i) & 1) {
                    ans *= now;
                    ans %= mod;
                }

                now *= now;
                now %= mod;
            }

            return ans;
        };

        ll ans = 1;
        int j = 0;

        while (k > 0) {
            auto func = [&](ll num) {
                ll ans = num;
                k--;

                ll act = min(k, (1LL << (min(31LL, num - 1))) - 1);

                ll count = 0;
                for (ll i = min(31LL, num - 1); i >= 1; i--) {
                    ll now = act / (1 << (i - 1)) - count;

                    ans *= fastpow(i, now);
                    ans %= mod;

                    count += now;
                }

                k -= count;

                return ans;
            };

            ans *= func(fds[j]);
            ans %= mod;
            j++;
        }

        cout << ans << '\n';
    }
}