#include <bits/stdc++.h>
#define IOS ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define rep(i, l, r) for (int i = l; i <= r; i++)
#define frep(i, l, r) for (int i = l; i >= r; i--)
#define eb emplace_back
#define pb push_back
#define endl "\n"
#define int long long
using namespace std;
using ll = long long;
using PII = pair<int, int>;
const int N = 2e5 + 3;
const int inf = 0x3f3f3f3f;
int a[N], b[N];
PII c[N];
void solve()
{
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    rep(i, 1, n)
    {
        cin >> a[i];
        c[i] = {a[i], 1};
    }
    rep(i, 1, m)
    {
        cin >> b[i];
        c[i + n] = {b[i], 2};
    }
    sort(c + 1, c + 1 + n + m);
    c[0] = {0, 2}, c[n + m + 1] = {w + 1, 2};
    // rep(i, 0, n + m + 1) cout << c[i].first << " " << c[i].second << endl;
    int pre = 0, st = 0;
    vector<int> v, ans;
    rep(i, 1, n + m + 1)
    {
        if (c[i].second == 1)
        {
            if (pre != 0 && pre + k - 1 >= c[i].first)
                continue;
            else
            {
                if (pre != 0)
                    v.push_back(pre);
                pre = c[i].first;
            }
        }
        else
        {
            if (pre == 0)
                continue;
            v.push_back(pre);
            int p = (int)v.size(), nxt = c[i].first;
            // cerr << "p:" << p << endl;
            // cerr << "st ed:" << st << " " << nxt << endl;
            for (int j = p - 1; j >= 0; j--) // end = nxt - 1
            {
                // cerr << v[j] << "-" << nxt << "-";
                if (v[j] + k - 1 >= nxt)
                    v[j] = nxt - 1 - k + 1;
                nxt = v[j];
                // cerr << nxt << " ";
            }
            if (v[0] <= st)
                return cout << "-1" << endl, void();

            st = c[i].first;
            pre = 0;
            for (auto k : v)
                ans.push_back(k);
            v.clear();
        }
    }
    cout << (int)ans.size() << endl;
    for (auto x : ans)
        cout << x << " ";
    cout << endl;
}

signed main()
{
    IOS;
    int T = 1;
    cin >> T;
    while (T--)
        solve();
}

/*

*/