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 Clib = Convert.ToInt64(tokens_n[2]);
long Croad = Convert.ToInt64(tokens_n[3]);
DisjointUnionSets sets = new DisjointUnionSets(n);
for (int a1 = 0; a1 < m; a1++)
{
string[] tokens_city_1 = Console.ReadLine().Split(' ');
int city_1 = Convert.ToInt32(tokens_city_1[0]) - 1;
int city_2 = Convert.ToInt32(tokens_city_1[1]) - 1;
sets.union(city_1, city_2);
}
long custoTotal = -999;
//Custo da biblioteca é menor que das estradas;
if (Clib <= Croad)
{
custoTotal = Clib * n;
}
else
{
int conexao = sets.countSets();
custoTotal = Clib * conexao + Croad * (n - conexao);
}
Console.WriteLine(custoTotal);
}
}
