#include <bits/stdc++.h>
using namespace std;

int t,n,m,k,w;
int a[100010],b[100010];
vector<pair<int,int>>p;

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>t;
    while(t--){
        p.clear();
        cin>>n>>m>>k>>w;
        for (int i=1;i<=n;i++) cin>>a[i];
        for (int j=1;j<=m;j++) cin>>b[j];
        int l,r=0,flag=1;
        sort(a+1,a+1+n);
        sort(b+1,b+1+m);
        int cnt=0;
        for (int i=1;i<=n;i++){
            if (r>=a[i]) continue;
            l=a[i];
            r=a[i]+k-1; 
            p.push_back({l,r});
            cnt++;
            //cout<<l<<' '<<r<<'\n';
        }
        int temp1=n,temp2=m;
        for (int i=cnt-1;i>=0;i--){
            l=p[i].first;
            r=p[i].second;
            if (r>w){
                int x=r-w;
                l-=x;
                r-=x;
            }
            //cout<<l<<' '<<r<<'\n';
            if (i!=cnt-1 && r>=p[i+1].first){
                int x=r-p[i+1].first+1;
                l-=x;
                r-=x;
            }
            //cout<<l<<' '<<r<<'\n';
            while(temp2>0 && b[temp2]>r) temp2--;
            while(temp2 && b[temp2]>=l){
                int x=r-b[temp2]+1;
                l-=x;
                r-=x;
                temp2--;
            }
            //cout<<l<<' '<<r<<'\n';
            if (l<=0 || a[temp1]>r){
                flag=0;
                break;
            }
            while(temp1 && a[temp1]>=l) temp1--;
            p[i]={l,r};
        }
        if (!flag){
            cout<<-1<<'\n';
            continue;
        }
        cout<<cnt<<'\n';
        for (int i=0;i<cnt;i++){
            cout<<p[i].first<<" ";
        }
        cout<<'\n';
    }
}