#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn=1e5+5;
#define db(x) cerr<<#x<<(x)<<" \n"
const int N = 2e5+10;
int kth;
void solve(){
 //   cout<<"Case# "<<++kth<<"\n";
    ll n,m,k,w,flag =0;
    cin>>n>>m>>k>>w;
    k--;
    using pli = pair<ll,ll>;
    vector<pli > a;
    for(int i=1;i<=n;i++){
        ll x;cin>>x;
        a.push_back({x,0});
    }
    for(int i=1;i<=m;i++){
        ll x;cin>>x;
        a.push_back({x,1});
    }
    a.push_back({0,1});
    a.push_back({w+1,1});
    sort(a.begin(),a.end());
    ll prel = 0,nowl =0,nowr =0,cntsum =0,num,anssum =0,dif =0;
    vector<ll> ans,pos;
    for(int i=0;i<a.size();i++){
        if(a[i].second)pos.push_back(i);
    }
    for(int i=1;i<pos.size();i++){
        ll left = a[pos[i-1]].first,right =a[pos[i]].first;
        //响铃黑点的左右边界
        cntsum =0,nowr =0,nowl =0,num=0,dif =0;
        int idx =pos[i]-1;
       // if(a[idx]!=left)cntsum+=a[pos[i]].first-a[idx].first-1;
        nowl =  a[pos[i]].first;
        vector<pli > start_pos;
    //    db(left),db(right);db(i);
      //  cout<<"[le,ri ]"<<left<<"          "<<right<<"\n";
        while(a[idx].first!=left){
            num++;nowr = a[idx].first;
            cntsum+=nowl-nowr-1;
            nowl = nowr-k;
            start_pos.push_back({nowl,nowr});
        //   cout<<"[idx ] "<<a[idx].first<<" nowr "<<nowr<<" nowl "<<nowl<<" \n";
            while(a[idx-1].second==0&&a[idx-1].first!=left&&a[idx-1].first>=nowl&&idx>=0){
                --idx;//一直向左遍历到第一个点；
       //         cout<<"idx"<<a[idx].first<<" \n";
            }
        //    cout<<"\n";
            idx--;
            if(idx<0)break;
          //  cout<<"ok\n";
        }
        reverse(start_pos.begin(),start_pos.end());
        if(num>0){
            
            if(nowl>left){
                anssum+=num;
                for(auto [x,y]:start_pos){
                    ans.push_back(x);
                }
            }
            else if(nowl<=left){
                dif = left-nowl+1;
                ll presum =0,pre =start_pos[0].first-1;
        //        cout<<"[dif,cntsum]"<<dif<<" "<<cntsum<<"\n";
                if(dif<=cntsum){
                    for(auto [x,y]:start_pos){
                        presum+= x-pre-1;
           //             cout<<"y = "<<x<<" presum "<<presum<<"\n";
                        ans.push_back(x+max(dif-presum,0ll));
                        
                    }
                }else {
                    flag =1;
                }
            }
        }
        if(flag)break;
    }
    if(flag){
        cout<<-1<<"\n";return;
    }
    cout<<ans.size()<<"\n";
    for(auto x:ans)cout<<x<<" ";cout<<"\n";
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int _=1;
    cin>>_;
    while(_--)solve();
    return 0;
}