#include<bits/stdc++.h>
using namespace std;
/*
ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
*/
// #define int long long
#define ld long double
//#define INT __int128
#define eb(x) emplace_back(x)
#define fi first
#define se second
#define sc(x) scanf("%d",&x)
#define SC(x) scanf("%lld",&x)
#define reserve reserve
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<long long, long long> PLL;
typedef pair<int, int> PII;
typedef pair<double, double> PDD;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int inf = 0x3f3f3f3f;
const LL mod = 1e9 + 7;
const ld eps = 1e-12;
const int N = 2e5 + 10, M = N + 10;
int n,m,k,w;
int red[N];

void solve(){
    cin>>n>>m>>k>>w;
    set<int>b;
    b.insert(0),b.insert(w+1);
    for(int i=1;i<=n;i++){
        scanf("%d",&red[i]);
    }
    for(int i=1;i<=m;i++){
        int a;
        scanf("%d",&a);
        b.insert(a);
    }
    sort(red+1,red+1+n);
    vector<int>ans;
    int l=0;
    while(1){
        auto pos=(b.upper_bound(l));
        if(pos==b.end())break;
        int r=*pos;

        // cout<<"____________ "<<l<<" "<<r<<endl;

        std::vector<PII> tmp;
        int be=upper_bound(red+1,red+1+n,l)-red;
        int end=lower_bound(red+1,red+1+n,r)-red;
        
        while(red[end]>=r)end--;

        // cout<<"_+++++++++++++++++++++  "<<be<<" "<<end<<endl;

        for(int i=be;i<=end;i++){
            PII t;
            t.first=red[i];
            t.second=red[i]+k-1;
            // for(;red[i]<=t.second;i++);
            while(i<=end&&red[i]<t.second)i++;
            tmp.emplace_back(t);
            // cout<<"============== "<<t.first<<" "<<t.second<<" "<<i<<" "<<be<<" "<<end<<endl;
        }

        for(int i=tmp.size()-1;i>=0;i--){
            if(tmp[i].second>=r){
                int t=tmp[i].second-r+1;    
                tmp[i].first-=t;
                tmp[i].second-=t;
            }
            else if(i<tmp.size()-1&&tmp[i].second>=tmp[i+1].first){
                int t=tmp[i].second-tmp[i+1].first+1;
                tmp[i].fi-=t;
                tmp[i].second-=t;
            }
            // cout<<"----------------  "<<tmp[i].first<<" "<<tmp[i].second<<" "<<i<<endl;
            // cout<<"22222222222"<<endl;
        }
        if(tmp.size()>0&&tmp[0].first<=l){
            puts("-1");
            return;
        }
        for(auto [f,s]:tmp){
            ans.emplace_back(f);
        }
        l=r;
    }
    cout<<ans.size()<<endl;
    for(int i=0;i<ans.size();i++){
        printf("%d ", ans[i]);
    }
    printf("\n");
}

signed main(){
    // ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
    int T=1,cas=1;
    cin>>T;
    while(T--){
        solve();
    }
    return 0;
}