有效地处理顾客的问题可以使其成为一名更为忠实的顾客。（)

A.Dealing effective with a customer who has a problem can make him/her into a more loyal customer

B.Dealing efficient with a customer who has a problem can make him/her into a more loyal customer

C.Dealing effectively with a customer who has a problem can make him/her into a more loyal customer

D.Dealing eficiency with a customer who has a problem can make him/her into a more loyal customer