#include<bits/stdc++.h>
#define mod 1000000007
using namespace std;
int powdv(int x,long long y=mod-2){
	int ans=1;
	while(y){
		if(y&1)ans=1ll*ans*x%mod;
		y>>=1,x=1ll*x*x%mod;
	}
	return ans;
}
int a[105];
int f[205];
#define poly vector<int>
void output(poly a){
	printf("### %d\n",(signed)a.size());
	for(auto cu:a)printf("%d ",cu);
	printf("\n");
}
poly multi(poly a,poly b){
	int n=a.size(),m=b.size();
	poly c(n+m-1);
	for(int i=0;i<n;++i)for(int j=0;j<m;++j){
		c[i+j]=(c[i+j]+1ll*a[i]*b[j])%mod;
	}
	return c;
}
poly zuo(poly a){
	int n=a.size();
	poly c(n+1);
	for(int i=0;i<n;++i)c[i+1]=a[i];
	return c;
}
poly qmo(poly a,poly b){
	int n=a.size(),m=b.size();
	if(n<m)return a;
	for(int i=n-1;i>=m-1;--i)for(int j=1;j<m;++j)
		a[i-j]=(a[i-j]-1ll*a[i]*b[m-1-j]%mod+mod)%mod;
	a.resize(m-1);
	return a;
}
poly qmod(long long n,poly p){
	if(n==0)return {1};
	poly q=qmod(n/2,p);
	poly qq=multi(q,q);
	if(n%2)qq=zuo(qq);
	return qmo(qq,p);
}
int main(){
	int n;
	long long c;
	scanf("%d%lld",&n,&c);
	for(int i=1;i<=n;++i){
		scanf("%d",&a[i]);
	}
	f[0]=1;
	for(int i=1;i<=n;++i){
		for(int j=1;j<=n;++j)f[j]=(f[j]+1ll*f[j-1]*a[i])%mod;
	}
	poly p={1};
	for(int i=1;i<=n;++i)p=multi(p,{mod-a[i],1});
	poly an=qmod(c,p);
	an.resize(n);
	int ans=0;
	for(int i=0;i<n;++i)ans=(ans+1ll*f[i]*an[i])%mod;
	for(int i=1;i<=n;++i){
		ans=(ans-powdv(a[i],c)+mod)%mod;
	}
	printf("%d\n",ans);
	return 0;
}