#include<iostream>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<ctime>
#define fuck(x) cout<<#x<<" = "<<x<<endl;
#define debug(a,i) cout<<#a<<"["<<i<<"] = "<<a[i]<<endl;
#define ls (t<<1)
#define rs ((t<<1)+1)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 100086;
const int maxm = 100086;
const int inf = 2.1e9;
const ll Inf = 999999999999999999;
const int mod = 1000000007;
const double eps = 1e-6;
const double pi = acos(-1);
ll num[maxn];
vector<ll>vec;
bool vis[maxn];
ll sum[maxn];
ll n,s,m,k;
int len;
struct node
{ll x;int id;
};
deque<node>q;
ll solve(int p){q.clear();for(int i=0;i<len;i++){vec.push_back(vec[i]);}for(int i=0;i<len;i++){vec.push_back(vec[i]);}ll ans=0;sum[0]=vec[0];for(int i=1;i<len*3;i++){sum[i]=sum[i-1]+vec[i];}for(int i=0;i<len*3;i++){while(!q.empty()&&q.back().x>sum[i]){q.pop_back();}if(!q.empty()&&q.front().id<i-p){q.pop_front();}q.push_back(node{sum[i],i});ans=max(ans,1ll*sum[i]-q.front().x);}return ans;
}int main()
{int T;scanf("%d",&T);int cases=0;while(T--){ll ans=0;cases++;scanf("%lld%lld%lld%lld",&n,&s,&m,&k);for(int i=1;i<=n;i++){scanf("%lld",&num[i]);}memset(vis,0,sizeof(vis));for(int i=1;i<=n;i++){vec.clear();if(vis[i]){continue;}int pos=i;for(int j=1;j<=m;j++){vec.push_back(num[pos]);vis[pos]=true;pos+=k;if(pos>n){pos%=n;}if(vis[pos]){break;}}len=vec.size();ll sum=0;for(int i=0;i<len;i++){sum+=vec[i];}if(sum<0){ans=max(ans,solve(len));}else{ans=max(ans,solve(m-(m/len-1)*len)+(m/len-1)*sum);}}printf("Case #%d: %lld\n",cases,max(0ll,s-ans));}return 0;
}