# https://yukicoder.me/problems/no/1554

MOD = 998244353
MAX_INT = 10 ** 18

class SegmentTree:
    """
    非再帰版セグメント木。
    更新は「加法」、取得は「最大値」のもの限定。
    """

    def __init__(self, init_array):
        n = 1
        while n < len(init_array):
            n *= 2
        
        self.size = n
        self.array = [ [MAX_INT, (0, 1)] for _ in range(2 * self.size)]
        for i, a in enumerate(init_array):
            self.array[self.size + i][0] = i
            self.array[self.size + i][1] = a
        
        end_index = self.size
        start_index = end_index // 2
        while start_index >= 1:
            for i in range(start_index, end_index):
                self._op(self.array[i], self.array[2 * i], self.array[2 * i + 1])
            end_index = start_index
            start_index = end_index // 2

    def _op(self, array, left, right):
        l = left[1]
        r  = right[1]
        if l[0] * r[1] >= l[1] * r[0]:
            array[0] = left[0]
            array[1] = left[1]
        else:
            array[0] = right[0]
            array[1] = right[1]

    def set(self, x, a):
        index = self.size + x
        self.array[index][1] = a
        while index > 1:
            index //= 2
            self._op(self.array[index], self.array[2 * index], self.array[2 * index + 1])

    def get_max(self, l, r):
        L = self.size + l; R = self.size + r

        # 2. 区間[l, r)の最大値を求める
        s = [MAX_INT, (0, 1)]
        while L < R:
            if R & 1:
                R -= 1
                self._op(s, s, self.array[R])
            if L & 1:
                self._op(s, s, self.array[L])
                L += 1
            L >>= 1; R >>= 1
        return s


def solve(N, K, A):
    init_array = [(A[i], 1) for i in range(N)]
    seg_tree = SegmentTree(init_array)

    answer = 1
    for _ in range(K):
        i, a = seg_tree.get_max(0, seg_tree.size)

        answer *= a[0]
        answer %= MOD
        answer *= pow(a[1], MOD - 2, MOD)
        answer %= MOD

        # 追加
        seg_tree.set(i, (a[0], a[1] + 1))
    
    # 計算
    a_sum = sum(A)
    a_sum %= MOD
    a_sum_p = pow(a_sum, K, MOD)
    a_sum_p_inv = pow(a_sum_p, MOD - 2, MOD)
    answer *= a_sum_p_inv
    answer %= MOD

    for k in range(1, K + 1):
        answer *= k
        answer %= MOD
    return answer


def main():
    T = int(input())
    answers = []
    for _ in range(T):
          N, K = map(int, input().split())
          A = list(map(int, input().split()))
          ans = solve(N, K, A)
          answers.append(ans)
    
    for ans in answers:
         print(ans)
    





if __name__ == "__main__":
    main()