#define _CRT_SECURE_NO_WARNINGS
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
ll lcm(ll a, ll b) { return 1ll * a * b / gcd(a, b); }
ll divCeil(ll x, ll y) { return x / y + (x % y != 0); }
const int MAXN = 2e5 + 5;
const double pi = 3.14159265358979323846;
const ll inf = 1e18;
double eps = 1e-9;
const int maxn = 2e5 + 5;
const int mod = 1e9 + 7;
#define endl "\n"
void solve() {
    int n, m, k, w;
    cin >> n >> m >> k >> w;
    vector<int>col(w + 5);//0 white, 1 red, 2 black
    vector<int>dp(w + 5, 1e9);
    vector<int>nxt(w + 5, 1e9);
    vector<int>vis(w + 5);
    vector<int>pre(w + 5);
    for (int i = 1; i <= n; i++) {
        int x;
        cin >> x;
        col[x] = 1;
    }
    for (int i = 1; i <= m; i++) {
        int x;
        cin >> x;
        col[x] = 2;
    }
    for (int i = 1; i <= w; i++) {
        pre[i] = pre[i - 1] + (col[i] == 2);
    }
    dp[0] = 0;
    for (int i = 1; i <= w; i++) {
        if (col[i] != 1)dp[i] = dp[i - 1];
        nxt[i] = i - 1;
        if (i < k || pre[i] - pre[i - k])continue;
        if (dp[i - k] + 1 < dp[i]) {
            nxt[i] = i - k;
            vis[i] = 1;
        }
        dp[i] = min(dp[i], dp[i - k] + 1);
    }
    int ans = (dp[w] >= 1e9 ? -1 : dp[w]);

    cout << ans << endl;
    if (ans != -1) {
        while (w>0) {
            if (vis[w])cout << w - k + 1 << " ";
            w = nxt[w];
        }
        cout << endl;
    }
    
    return;
}
signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int t;
    cin >> t;
    while (t--)solve();
    return 0;
}