#include <bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define st first
#define nd second
#define pb push_back
#define mpr make_pair
using namespace std;
inline int read(){
	int x=0,f=1;char ch=getchar();
	for(;!isdigit(ch);ch=getchar())f^=ch=='-';
	for(;isdigit(ch);ch=getchar())x=x*10+(ch^48);
	return f?x:-x;
}
const int N=2e5+5;
pii A[N];
int n,m,w,k,qh,qt,que[N],ans,b[N],tot;
vector<int> oper;
int f[N],g[N],nxt[N];
int work(int l,int r){
	tot=0;
	for(int i=1;i<=qt;++i)b[++tot]=que[i]-l;
	r-=l;
	for(int i=0;i<=tot;++i){
		f[i]=g[i]=nxt[i]=-1;
	}
	f[0]=g[0]=0;
	que[qh=qt=1]=0;
	b[tot+1]=r;
	for(int i=1;i<=tot;++i){
		int l=0,r=i,FIND=-1;
		while(l<=r){
			int mid=(l+r)>>1;
			if(b[i]-b[mid]>=k)FIND=mid,l=mid+1;
			else r=mid-1;
		}
		if(FIND==-1){
			if(b[i+1]>k){
				f[i]=1;
				g[i]=k;
				que[++qt]=i;
				nxt[i]=0;
			}
		}
		else{
			while(qh<=qt&&que[qh]<FIND)++qh;
			if(qh<=qt){
				if(g[que[qh]]+k<b[i+1]){
					g[i]=max(b[i],g[que[qh]]+k);
					f[i]=f[que[qh]]+1;
					nxt[i]=que[qh];
					que[++qt]=i;
				}
			}
			else{
				return -1;
			}
		}
	}
	if(f[tot]==-1)return -1;
	int p=tot;
	while(p){
		oper.pb(g[p]-k+1+l);
		p=nxt[p];
	}
	return f[tot];
}
void solve(){
	ans=0;
	oper.clear();
	n=read(),m=read(),k=read(),w=read();
	for(int i=1;i<=n;++i)A[i]=mpr(read(),1);
	for(int i=1;i<=m;++i)A[i+n]=mpr(read(),0);
	A[n+m+1]=mpr(w+1,0);
	n=n+m+1;
	sort(A+1,A+n+1);
	int last=0;
	qh=1,qt=0;
	for(int i=1;i<=n;++i){
		if(A[i].nd==0){
			int t=work(last,A[i].st);
			if(t==-1){puts("-1");return;}
			ans+=t;
			last=A[i].st;
			qh=1,qt=0;
		}
		else{
			que[++qt]=A[i].st;
		}
	}
	printf("%lld\n",ans);
	sort(oper.begin(),oper.end());
	for(int x:oper)printf("%lld ",x);
	puts("");
}
signed main(){
	for(int cas=read();cas--;)solve();
}