#include<bits/stdc++.h>
#include<algorithm>
#include<vector>
using namespace std;
#define ll long long
const int N = 2e5 + 10, INF = 0x3f3f3f3f;
//int cnt[N];
 
void solve() {
	ll n, m, k, w; cin >> n >> m >> k >> w;
	set<ll>v1;//red
	vector<ll>v2;//black
	vector<ll>ans;//答案数组
	ll x; v2.push_back(0); v2.push_back(w + 1);//边界
	for (ll i = 0; i < n; ++i) {
		cin >> x; v1.insert(x);
	}
	for (ll i = 0; i < m; ++i) {
		cin >> x; v2.push_back(x);
	}
	sort(v2.begin(), v2.end());
	//处理每区间
	ll le = 0; auto rit = v1.begin();//区间左黑边界下标,红格子指针
	while (le <= v2.size() - 2) {
		ll lef = v2[le], rig = v2[le + 1];
		if (lef == rig - 1) { le++; continue; }
		//ll sta = lef + 1;
		ll bered =0;//上一个红格子的位置
		while (rit!=v1.end()&&*rit < rig) { 
			if (*rit - bered >= k||rit==v1.begin()) {
				ans.push_back(*rit);
				//cout << *rit << "push" << endl;
				bered = *rit;
			}
				rit++;
		}
		//cout << bered <<"bred"<< rig<<endl;
		if (bered+k-1 >= rig) {//需要左移每个区间
			ans[ans.size() - 1] -= bered+k- rig;
			//cout << ans[ans.size() - 1] << "change" << endl;
			if (ans[ans.size() - 1] <= lef) { cout << -1 << endl; return; }
			//查看是否区间重叠
			for (ll i = ans.size() - 1; i - 1 >= 0 && ans[i - 1] > lef; --i) {
				ll zuo = ans[i];//每个小区间的左边界
				ll szuo = ans[i - 1];
				//cout << ans[i - 1] << "ans[i-1]" << lef << endl;
				if (zuo - szuo < k) {
					ans[i - 1] -= k - (zuo - szuo);//左移上一个区间
				}
				if (ans[i - 1] <= lef) { cout << -1 << endl; return; }
			}
		}
		//if (sta <= lef) { cout << -1 << endl; return; }
		le++;
	}
	cout << ans.size() << endl;
	for (ll i = 0; i < ans.size(); ++i) { cout << ans[i] << " "; }
	cout << endl;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	int t; cin >> t;
	while (t--) {
		solve();
	}
	return 0;
}