1976

/*
DP[i][j],以i结尾j个火车头的最大载人数
DP[i][3] = max(DP[i][3],DP[i-M][2]+DP[i][1],DP[i-1][3]); 
DP[i][2] = max(DP[i][2],DP[i-M][1]+DP[i][1],DP[i-1][2]);
DP[i][1] = max(DP[i][1],DP[i-1][1]);
*/

// include file
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cctype>
#include <ctime>

#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <bitset>

#include <algorithm>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <list>
#include <functional>

using namespace std;

// typedef
typedef __int64 LL;

// 
#define read freopen("in.txt","r",stdin)
#define write freopen("out.txt","w",stdout)

#define Z(a,b) ((a)<<(b))
#define Y(a,b) ((a)>>(b))

const double eps = 1e-6;
const double INFf = 1e100;
const int INFi = 1000000000;
const LL INFll = (LL)1<<62;
const double Pi = acos(-1.0);

template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T TMAX(T x,T y)
{
	if(x>y) return x;
	return y;
}
template<class T> inline T TMIN(T x,T y)
{
	if(x<y) return x;
	return y;
}
template<class T> inline T MMAX(T x,T y,T z)
{
	return TMAX(TMAX(x,y),z);
}
template<class T> inline T MMIN(T x,T y,T z)
{
	return TMIN(TMIN(x,y),z);
}
template<class T> inline void SWAP(T &x,T &y)
{
	T t = x;
	x = y;
	y = t;
}


// code begin
int T,N,M;
int DP[50010][4];
int data[50010];
int main()
{
	read;
	write;
	int sum;
	scanf("%d",&T);
	while(T--)
	{
		scanf("%d",&N);
		for(int i=0;i<N;i++) scanf("%d",data+i);
		scanf("%d",&M);
		memset(DP,0,sizeof(DP));
		sum = 0;
		for(int i=0;i<M;i++) sum+=data[i];
		DP[M-1][1] = sum;
		for(int i=M;i<N;i++)
		{
			sum = sum - data[i-M] + data[i];
			DP[i][1] = sum;
		}

		for(int i=M;i<N;i++)
		{
			DP[i][3] = TMAX(DP[i][3],DP[i-M][2]+DP[i][1]); DP[i][3] = TMAX(DP[i-1][3],DP[i][3]);
			DP[i][2] = TMAX(DP[i][2],DP[i-M][1]+DP[i][1]); DP[i][2] = TMAX(DP[i-1][2],DP[i][2]);
			DP[i][1] = TMAX(DP[i-1][1],DP[i][1]);
		}

		printf("%d\n",DP[N-1][3]);
	}
	return 0;
}