#include <bits/stdc++.h>
#include <iostream>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
#define i128 _int128
#define fi first
#define se second 
#define pb push_back
#define endl '\n'
//#define int long long

const ll INF=0x3f3f3f3f;
const int N=1e9,M=1e9+9;
const ll mod=998244353;

int read(){
	int s=0,w=1;
	char c=getchar();
	while(!isdigit(c)) (c=='-')?w=-1:w=1,c=getchar();
	while(isdigit(c)) s=(s<<1)+(s<<3)+(c^48),c=getchar();
	return s*w;
}

int qpow(int a,int b){
    a%=mod;
    int res=1;
    while(b){
        if(b&1){res=(res*a)%mod;}
        a=(a*a)%mod;
        b>>=1;
    }
    return res%mod;
}

// int inverse(int a){
//     a%=mod;
// 	return qpow(fac[a%mod],mod-2)%mod;
// }

// int C(int n,int r){
//     n%=mod,r%=mod;
//     if(r>n)return 0;
//     return ((fac[n%mod]*inverse(r))%mod*inverse(n-r))%mod;
// }

// int Lucas(int n,int r){
//     if(r==0)return 1;
//     return C(n%mod,r%mod)%mod*Lucas(n/mod,r/mod)%mod;
// }

int n,m,k,w;

void solve(){
    deque<int> ans;//答案下标存放
    priority_queue<int,vector<int>,greater<int> > id,id1,r,b;//红黑格下标存放
    map<int,int> s,vis;//红黑格空间、标记存放，黑不包含自己，红包含
    // int sr=0,sb=0;//红黑格空间计算媒介
    int ir=0,ib=0;//上个红、黑格下标

    cin>>n>>m>>k>>w;
    for(int i=1;i<=n;++i){
        int x;cin>>x;r.push(x);
        vis[x]=1;
        id.push(x);id1.push(x);
    }
    for(int i=1;i<=m;++i){
        int x;cin>>x;b.push(x);
        vis[x]=2;
        id.push(x);id1.push(x);
    }
    b.push(w+1),vis[w+1]=2;
    id.push(w+1),id1.push(w+1);//最右侧
    while(!id.empty()){
        int temp=id.top();id.pop();
        if(vis[temp]==1){s[temp]=temp-max(ir,ib),ir=temp;}
        if(vis[temp]==2){s[temp]=temp-ib-1,ir=0,ib=temp;}
        //cout<<temp<<':'<<s[temp]<<" "<<id.size()<<endl;//test
    }

    int cnt=0;
    int res=0;//上条strip可向右滑动的最大空间
    while(!id1.empty()){
        int i=id1.top();id1.pop();
        if(vis[i]==1){//红格
            if(s[i]<=res){//前一条可向右滑动覆盖当前红格
                //cout<<i<<' '<<"case11"<<endl;
                //cout<<s[i]<<endl;
                int temp=ans.back();ans.pop_back();
                temp+=s[i];res-=s[i];
                ans.push_back(temp);
                r.pop();//弹出已用过的格
                if(b.top()>r.top()){
                    //cout<<r.top()<<' '<<s[r.top()]<<endl;
                    s[r.top()]-=(s[i]-1);//更新下一红格空间
                    //cout<<s[r.top()]<<endl;
                }
            }                
            else if(s[i]>=k){//红格前面空间足够放整条strip
                //cout<<"case12"<<endl;
                ans.push_back(i-k+1);cnt++;
                res=s[i]-1;
                r.pop();
                s[b.top()]-=k;
            }
            else{
                if(s[b.top()]>=k){//后面空间足够放剩余strip
                    //cout<<i<<' '<<"case131"<<endl;
                    ans.push_back(i-s[i]+1);cnt++;
                    res=s[i]-1;
                    r.pop();
                    s[b.top()]-=k;
                    if(b.top()>r.top())s[r.top()]-=k-s[i];
                }
                else{//无法放strip   
                    //cout<<"case132"<<endl;                     
                    cout<<-1<<endl;return;
                }
            }
            
        }
        else if(vis[i]==2){//黑格
            //cout<<"case12"<<endl;
            res=0;
            b.pop();//弹出已用过的格
        }
    }
    cout<<cnt<<endl;
    for(auto x:ans)cout<<x<<' ';
}
 
 
signed main(){
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    
    int _=1;
    // fac[0]=1;
    // for(int i=1;i<=N-9;++i)fac[i]=(fac[i-1]*i)%mod;
    cin>>_;
    
    while(_--)solve();
 
    return 0;
}