#include <bits/stdc++.h>
#define ll long long int
#define endl "\n"
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define ump unordered_map
#define yes cout<<"YES"<<"\n"
#define no cout<<"NO"<<"\n"
const ll M = 998244353;
const ll N = 2e5 + 10;
const ll INF = 1e9+7;
const int dx[] = {-1, 1, 0, 0}; 
const int dy[] = {0, 0, -1, 1}; 
using namespace std;
 
 
vector<ll> graph[N];
ll visited[N];
 
void reset() {
    for(ll i = 0; i < N; i++) {
        graph[i].clear();
        visited[i] = 0;
    }
}
 
ll dfs(ll vertex) {
    visited[vertex] = 1;
    ll ct = 1;
    for(ll child : graph[vertex]) {
        if(visited[child]) continue;
        ct += dfs(child);
    }
    return ct;
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    ll t; cin >> t;
    while(t--) {
        reset();
        ll n, m, l, r; cin >> n >> m >> l >> r;
        for(ll i = 0; i < m; i++) {
            ll v1, v2;
            cin >> v1 >> v2;
            graph[v1].pb(v2);
            graph[v2].pb(v1);
        }
        ll cost = 0;
        for(ll i = 1; i <= n; i++) {
            if(!visited[i]) {
                ll num = dfs(i);
                ll need = l + r*(num-1);
                cost += need;
            }
        }
        cout<<min(n*l, cost)<<endl;
    }
}

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

MgozIDMgMiAxCjEgMgozIDEKMiAzCjYgNiAyIDUKMSAzCjMgNAoyIDQKMSAyCjIgMwo1IDY=

2
3 3 2 1
1 2
3 1
2 3
6 6 2 5
1 3
3 4
2 4
1 2
2 3
5 6