using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace RoadsNLibraries
{
    class RoadsNLibraries
    {
        static Dictionary<int, List<int>> adj = new Dictionary<int, List<int>>();
        static List<bool> visited = new List<bool>();
        static int nodes = 0;
        static long cost = 0;

        static void DFS(int n)
        {
            nodes++;
            visited[n] = true;
            foreach (int i in adj[n])
            {
                if (!visited[i])
                {
                    DFS(i);
                }
            }
            return;
        }

        static void clear()
        {
            adj.Clear();
            cost = 0;
            nodes = 0;
        }

        static void Main(String[] args)
        {

            int q = Convert.ToInt32(Console.ReadLine());
            for (int a0 = 0; a0 < q; a0++)
            {
                string[] tokens_n = Console.ReadLine().Split(' ');
                int n = Convert.ToInt32(tokens_n[0]);
                int m = Convert.ToInt32(tokens_n[1]);
                long x = Convert.ToInt64(tokens_n[2]);
                long y = Convert.ToInt64(tokens_n[3]);


                for (int a1 = 0; a1 < m; a1++)
                {
                    string[] tokens_city_1 = Console.ReadLine().Split(' ');
                    int city_1 = Convert.ToInt32(tokens_city_1[0]);
                    int city_2 = Convert.ToInt32(tokens_city_1[1]);
                    if (adj.ContainsKey(city_1))
                    {
                        adj[city_1].Add(city_2);
                    }
                    else
                    {
                        adj.Add(city_1, new List<int>() { city_2 });
                    }
                    if (adj.ContainsKey(city_2))
                    {
                        adj[city_2].Add(city_1);
                    }
                    else
                    {
                        adj.Add(city_2, new List<int>() { city_1 });
                    }

                }

                cost = 0;
                visited = Enumerable.Repeat(false, n + 1).ToList();
                for (int i = 1; i <= n; ++i)
                {

                    if (!visited[i])
                    {
                        if(adj.ContainsKey(i))
                            DFS(i);
                        cost = cost + x;
                        if (x > y)
                            cost = cost + (y * Math.Max(0,(nodes - 1)));
                        else
                            cost = cost + (x * Math.Max(0, (nodes - 1)));

                    }
                }

                Console.WriteLine(cost);
                clear();
            }
            Console.Read();
        }
    }
}