#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define vi vector<int>
#define vll vector<long long>
#define double long double
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<'*'<<x<<'\n';
#define yes cout<<"YES\n";
#define no cout<<"NO\n";
#define rep(x, y) for(int i=(x); i<=(y); i++)
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
const int INF=0x3f3f3f3f;
const ll LINF=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
ll gcd(ll a,ll b)
{
	return b?gcd(b,a%b):a;
}
ll lcm(ll a,ll b)
{
	return a*b/gcd(a,b);
}
ll qmi(ll a,ll b)
{
	ll ans=1;
	while(b)
	{
		if(b&1)ans=ans*a%mod;
		a=a*a%mod;
		b>>=1;
	}
	return ans;
}




void solve()
{
//	debug("**********");
	map<int, int>l, r;
	map<int, bool>ok;
	int n, m, k, w;
	cin >> n >> m >> k >> w;
	vi red;
	red.pb(0);
	rep(1, n)
	{
		int x; cin >> x;
		red.pb(x);
	}
	sort(all(red));
	rep(1, m)
	{
		int x; cin >> x;
		int lo = 0, ri = n;
		while(lo < ri)
		{
			int mid = (lo + ri + 1) >> 1;
			if(red[mid] < x)lo = mid;
			else ri = mid - 1;
		}
		if(!l[lo])l[lo] = x;
		else l[lo] = min(l[lo], x);
		if(!r[lo])r[lo] = x;
		else r[lo] = max(r[lo], x);
		ok[lo] = 1;
//		debug(lo);
	}
//	rep(0, n-1)
//	{
//		if(ok[i])cout << i << ' ';
//	}
	int L = red[1], R = red[1], preR = 0;
	int lidx = 1, ridx = 1;
	vi res;
	int i = 1;
	while(i <= n)
	{
		if(ok[i-1] && ok[i] && l[i] - r[i-1] + 1 < k)
		{
			cout << -1 << endl;
			return;
		}
		L = max(preR+1, red[i]), lidx = i, ridx = i;
		while(1)
		{
			if(!ok[ridx] && ridx < n && red[ridx+1] - L + 1 <= k)ridx++;
			else break;
		}
//		debug(ridx);
		R = red[ridx];
//		debug(L);
		int len = R - L + 1;
		int diff = k - len;
		
		int L2 = L;
		L = max({r[i-1]+1, L - diff, preR+1});
		
		diff -= (L2 - L);
		if(ok[ridx])R = min(l[ridx]-1, R+diff);
		else R += diff;
//		cout << "L=" << L << endl;
//		cout << "R=" << R << endl;
//		cout << "ridx=" << ridx << endl;
//		cout << "lidx=" << lidx << endl;
		res.pb(L);
		if(R - L + 1 != k || R > w)
		{
			cout << -1 << endl;
			return;
		}
		i = max(i, ridx) + 1;
		preR = R;
	}
	cout << res.size() << endl;
	for(int x:res)cout << x << ' ';
	cout << endl;
}



signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int _;
	_=1;
	cin>>_;
	while(_--)solve();
	return 0;
}