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

const int N = 1e5;

int f[N];
int a[N], b[N];
int K;
vector<int> ans;

bool solve(int l, int r, int L, int R){
    int t = l, lst = L;

    vector<int> res;
    while(1){
        int u = lower_bound(a + t + 1, a + r + 1, a[t] + K) - a;
        int pos = max(lst, a[u - 1] - K + 1);
        res.push_back(pos); lst = pos + K;
        if(lst > R + 1)break;
        t = u;
        if(t > r)break;
    }

    if(t > r){
        for(int u : res)ans.push_back(u);
        return 1;
    }

    res.clear();
    t = r;
    lst = R;
    while(1){
        int u = upper_bound(a + l, a + t + 1, a[t] - K) - a;
        int pos = min(lst - K + 1, a[u]);
        res.push_back(pos); lst = pos - 1;
        if(lst < L - 1)break;
        t = u - 1;
        if(t < l)break;
    }

    if(t < l){
        for(int u : res)ans.push_back(u);
        return 1;
    }

    return 0;
}

void solve(){
    ans.clear();
    int n, m, w;
    scanf("%d%d%d%d", &n, &m, &K, &w);

    for(int i = 1; i <= n; i ++)scanf("%d", &a[i]);
    for(int i = 1; i <= m; i ++)scanf("%d", &b[i]);
    b[++ m] = 0; b[++ m] = w + 1;

    sort(a + 1, a + n + 1);
    sort(b + 1, b + m + 1);

    int j = 1;
    for(int i = 1; i < m; i ++){
        int l = j;
        while(j <= n && a[j] < b[i + 1])j ++;
        if(!solve(l, j - 1, b[i] + 1, b[i + 1] - 1)){
            puts("-1");
            return ;
        }
    }

    printf("%d\n", (int)ans.size());

    for(int u : ans){
        printf("%d ", u);
    }
    puts("");
}

int main(){
    // freopen("in", "r", stdin);

    int T;
    scanf("%d", &T);

    while(T --)solve();
}