#include<bits/stdc++.h>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x...) do{cout << "\033[32;1m" << #x << "->" ; err(x);} while(0)
void err(){cout << "\033[39;0m" << endl;}
template<template<typename...> class T,typename t,typename... A>
void err(T<t> a,A... x){for (auto v:a) cout << v << ' '; err(x...);}
template<typename T,typename... A>
void err(T a,A... x){cout << a << ' '; err(x...);}
#else
#define dbg(...)
#endif
typedef long long ll;
typedef pair<int,int> pi;
typedef vector<int> vi;
template<class T> using vc=vector<T>;
template<class T> using vvc=vc<vc<T>>;
template<class T> void mkuni(vector<T>&v)
{
    sort(v.begin(),v.end());
    v.erase(unique(v.begin(),v.end()),v.end());
}
template<class T>
void print(T x,int suc=1)
{
    cout<<x;
    if(suc==1) cout<<'\n';
    else cout<<' ';
}
template<class T>
void print(const vector<T>&v,int suc=1)
{
    for(int i=0;i<v.size();i++)
        print(v[i],i==(int)(v.size())-1?suc:2);
}
#define pb push_back
#define lowbit(x) x & -x
#define int long long
const int N=2e5+7;
const int mod=998244353;
ll quick(ll x, ll y) {
	ll res=1;
	while(y) {
		if(y&1) res=res*x%mod;
		x=x*x%mod;
		y>>=1;
	}
	return res;
} 
int t,n,k;
int a[101010];
int X[101010];
void solve() {
	auto cmp = [](int L,int R) {
		return 1LL*a[L]*(X[R]+1)<1LL*a[R]*(X[L]+1);
	};
	priority_queue<int,vector<int>,decltype(cmp)> pq(cmp);
	cin>>n>>k;
	ll s=0;
	for(int i=0;i<n;++i) {
		cin>>a[i];
		s+=a[i];
		X[i]=0;
		pq.push(i);
	}
	ll ans=1;
	for(int i=0;i<k;++i) {
		int x=pq.top();
		pq.pop();
		X[x]++;
		ans=ans*(1+i)%mod;
		ans=ans*quick(X[x],mod-2)%mod;
		ans=ans*a[x]%mod;
		ans=ans*quick(s,mod-2)%mod;
		pq.push(x);
	}
	print(ans);
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int t;
	cin>>t;
	while(t--)  solve();
}