#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
const int N=1e5+5,mod=1e9+7;
long long r[N];
int main(){
    freopen("Milk.in","r",stdin);
    freopen("Milk.out","w",stdout);
    int n,d,a,b;
    cin>>n>>d>>a>>b;
    for(int i=1;i<=n;i++){
        cin>>r[i];
    }
    while(d--){
        sort(r+1,r+1+n);
        int p=n-b;
        for(int i=1;i<=a-b;i++){
            r[p]++;
            p--;
        }
    }
    long long ans=0;
    for(int i=1;i<=n;i++){
        r[i]%=mod;
        ans=(ans+(r[i]*r[i])%mod)%mod;
    }
    cout<<ans;
    return 0;
}