class vertex:
	def __init__(self,color=None,adj_list=[]):
		self.color=color
		self.d=d
		self.f=f
		self.parent=parent
		self.adj_list=adj_list

class graph:
	def __init__(self,n):
		self.n=n
		self.list=[None]*n
		for i in xrange(n):
			self.list[i]=vertex()

def DFS(G):
	for i in xrange(G.n):
		G.list[i].color='white'
	global time
	time = 0
	for i in xrange(G.n):
		if G.list[i].color=='white':
			time=time+clib-croad
			DFS_VISIT(G,i)
	return time

def DFS_VISIT(G,i):
	global time
	time=time+croad
	G.list[i].color='gray'
	for j in G.list[i].adj_list:
		if G.list[j-1].color=='white':
			G.list[j-1].parent=i+1
			DFS_VISIT(G,j-1)
	G.list[i].color='black'

q=input()
for i in xrange(q):
	n,m,clib,croad=map(int,raw_input().split())
	G=graph(n)
	for j in xrange(m):
		v1,v2=map(int,raw_input().split())
		G.list[v1-1].adj_list.append(v2)
		G.list[v2-1].adj_list.append(v1)
	if clib<=croad:
		print clib*n
	else:
		print DFS(G)