#include <bits/stdc++.h>
#define int long long
using namespace std;
void solve()
{
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    vector<int> a(n + 1);
    vector<int> b(m + 2);
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    b[0] = 0;
    b[m + 1] = w + 1;
    for (int i = 1; i <= m; i++)
        cin >> b[i];
    sort(a.begin(), a.end());
    int idx = 1;
    sort(b.begin(), b.end());
    vector<int> res;
    //0 7 8
    for (int i = 1; i <= m + 1; i++)
    {
        int l = b[i - 1] + 1, r = b[i];//[l,r)可以放
        // cout << l << ' '<< r << endl;
        if(l >= r)
        {
            continue;
        }
        vector<int> c;//存放该区间的红格子
        while (idx <= n && a[idx] < l) {
            // 如果有红格子在上一个区间未覆盖到这里会有问题。
            // 具体根据题意判断是否应-1结束，这里假设上个区间已成功覆盖
            idx++;
        }
        while (idx <= n && l <= a[idx] && a[idx] < r)
        {
            c.push_back(a[idx++]);
        }
        vector<int> t;
        int rr = l - 1;
        for (auto &lr : c)
        {

            if (lr > rr)
            {
                t.push_back(lr);
                rr = lr + k - 1;
            }
        }
        //存放
        int idx = t.size() - 1;
        while (idx >= 0 && t[idx] + k - 1 >= r)
        {
            t[idx] = r - k;
            r = t[idx];
            idx--;
        }
        if (l >= r)
        {
            puts("-1");
            return;
        }
        res.insert(res.end(), t.begin(), t.end());
    }
    cout << res.size() << endl;
    for (auto &item : res)
    {
        cout << item << ' ';
    }
    cout << endl;
    return;
}
signed main()
{
    int t = 1;
    cin >> t;
    while (t--)
        solve();
}