#include<bits/stdc++.h>
#define int long long
#define pii pair<int, int>
#define ll long long
using namespace std;
int n, m, k, w;
void solve() {
    cin >> n >> m >> k >> w;
    bool flag = 1;
    vector<int> blk, red, ans;
    for (int i = 1; i <= n; i++){
        int x;
        cin >> x;
        red.push_back(x);
    }
    for(int i = 1; i <= m; i++){
        int x;
        cin >> x;
        blk.push_back(x);
    }
    blk.push_back(0);
    blk.push_back(w + 1);
    sort(red.begin(), red.end());
    sort(blk.begin(), blk.end());
    int j = 0;
    for (int i = 1; i < blk.size(); i++){
        int L = blk[i-1] + 1, R = blk[i];
        vector<int> now, tmp;
        while (j < red.size() && red[j] < blk[i])
            now.push_back(red[j]), j++;
        int l = L, space = 0;
        for(auto x : now){
            if(l > x)
                continue;
            space += (x - l);    
            l = x + k;
            tmp.push_back(x);
        }
        if(l > R && l - R > space){
            flag = 0;
            break;
        }
        space = l - R;
        for (int t = tmp.size() - 1; t >= 0; t--){
            ans.push_back(tmp[t] - space);
            space -= min(space, tmp[t] - tmp[t - 1] - k);
        }
    }
    if(!flag) cout << "-1\n";
    else {
        sort(ans.begin(), ans.end());
        cout << ans.size() << '\n';
        for(auto x : ans)
            cout << x << ' ';
        cout << '\n';
    }
}
signed main() {
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t = 1;
     cin >> t;
    while (t--)
        solve();
    return 0;
}