import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int q = in.nextInt(); // number of queries
        for(int a0 = 0; a0 < q; a0++){

            int n = in.nextInt(); // number of cities
            int m = in.nextInt(); // number of roads
            long c_lib = in.nextLong(); // cost to repair library
            long c_road = in.nextLong(); // cost to repair road
            HashMap<String, HashSet<Integer>> graph = new HashMap<String, HashSet<Integer>>(n);
            for(int a1 = 0; a1 < m; a1++){
                int city_1 = in.nextInt();
                int city_2 = in.nextInt();
                addConnection(graph, city_1, city_2);
                addConnection(graph, city_2, city_1);
            }

            boolean fixRoads = true;
            if (c_lib <= c_road) {
                fixRoads = false;
            }

            BigInteger libraryCost = BigInteger.valueOf(c_lib);
            BigInteger roadCost = BigInteger.valueOf(c_road);
            BigInteger totalCost = new BigInteger("0");

            HashSet<Integer> visitedCities = new HashSet<Integer>(n);

            for (Map.Entry<String, HashSet<Integer>> entry : graph.entrySet()) {
                Stack<Integer> searchList = new Stack<Integer>();
                Integer startCity = Integer.valueOf(entry.getKey());
                if (!visitedCities.contains(startCity)) {
                    visitedCities.add(startCity);
                    totalCost = totalCost.add(libraryCost);
                    if (fixRoads) {
                        for (Integer nextCity : entry.getValue()) {
                            searchList.push(nextCity);
                        }
                    }
                }
                while(!searchList.empty()) {
                    Integer thisCity = searchList.pop();
                    if (!visitedCities.contains(thisCity)) {
                        visitedCities.add(thisCity);
                        totalCost = totalCost.add(roadCost);
                        HashSet<Integer> adjacentCities = graph.get(String.valueOf(thisCity));
                        for (Integer nextCity : adjacentCities) {
                            searchList.push(nextCity);
                        }
                    }
                }
            }

            BigInteger numLonelyCities = BigInteger.valueOf(n - visitedCities.size());
            totalCost = totalCost.add(numLonelyCities.multiply(libraryCost));

            System.out.println(totalCost);
        }
    }

    private static void addConnection(HashMap<String, HashSet<Integer>> graph, int fromCity, int toCity) {
        HashSet<Integer> adjacentCities = graph.get(String.valueOf(fromCity));
        if(adjacentCities == null) {
            adjacentCities = new HashSet<Integer>();
            graph.put(String.valueOf(fromCity), adjacentCities);
        }
        adjacentCities.add(toCity);
    }
}