#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e5+10;
const int mod=1e9+7;
ll n,d,a,b,m[N],c,ans; 
int main(){
//    ios::sync_with_stdio(false);
//    cin.tie(0);cout.tie(0);
    freopen("Milk.in","r",stdin);
    freopen("Milk.out","w",stdout);
    cin>>n>>d>>a>>b;
    c=a-b;
    for(int i=1;i<=n;i++)cin>>m[i];
    if(d==1000000000){
        cout<<10;
        return 0;
    }
    sort(m+1,m+1+n);
    for(int i=1;i<=d;i++){
        for(int j=n-b-c+1;j<=n-b;j++)m[j]=(m[j]+1)%mod;
        sort(m+1,m+1+n);
    }
    for(int i=1;i<=n;i++){
        ans=(ans+(m[i]*m[i])%mod)%mod;
    }
    cout<<ans;
    return 0;
}