#include<bits/stdc++.h>

#define ll long long
#define pi pair<int,int>
#define vi vector<int>
#define cpy(x,y,s) memcpy(x,y,sizeof(x[0])*(s))
#define mset(x,v,s) memset(x,v,sizeof(x[0])*(s))
#define all(x) begin(x),end(x)
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define ary array
#define eb emplace_back
#define IL inline

using namespace std;

#define N 500005

int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<'0' || ch>'9')f=(ch=='-'?-1:f),ch=getchar();
    while(ch>='0' && ch<='9')x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
    return x*f;
}
void write(int x){
    if(x<0)x=-x,putchar('-');
    if(x/10)write(x/10);
    putchar(x%10+'0');
}

int f[N],a[N],g[N],pre[N];
map<int,int> t;
set<int> S,B;

void solve(){
    int n=read(),m=read(),k=read(),w=read();B.clear();S.clear();t.clear();
    B.insert(0);B.insert(w+1);
    for(int i=1;i<=n;i++)a[i]=read(),S.insert(a[i]);
    sort(a+1,a+n+1);
    for(int i=1;i<=n;i++)t[a[i]]=i;
    for(int i=1,p=0;i<=m;i++)p=read(),B.insert(p);
    for(int i=1;i<=n;i++)f[i]=-1;
    for(int i=1;i<=n;i++){
        auto it=B.lower_bound(a[i]);
        int R=(*it)-1,L=(*prev(it))+1;
        if(R-L+1<k)return write(-1),putchar('\n'),void();
        R=min(R-k+1,a[i]);L=max(L,a[i]-k+1);
        int pos=t[*(S.lower_bound(L))];
        if(f[pos-1]==-1 || (pos-1!=0 && g[pos-1]+k-1>L))continue;
        f[i]=f[pos-1]+1;g[i]=L;pre[i]=pos-1;
        //cerr<<i<<' '<<g[i]<<' '<<a[i]<<' '<<f[i]<<' '<<pre[i]<<endl;
    }
    if(f[n]==-1)return write(-1),putchar('\n'),void();
    write(f[n]);putchar('\n');
    int u=n;vi res;
    while(u){
        res.pb(g[u]);u=pre[u];
    }
    reverse(all(res));
    for(auto v:res)write(v),putchar(' ');putchar('\n');
}

int main(){
    #ifdef EAST_CLOUD
    freopen("a.in","r",stdin);
    //freopen("a.out","w",stdout);
    #endif
 
    int T=read();while(T--)solve();
    return 0;
}