Which of the following is a common practice for ensuring the quality of customer service?

Which of the following is a common practice for ensuring the quality of customer service?

A.
Asking customers to participate in a blog

B.
Notifying the customer’s credit card company via e-mail that a purchase has occurred

C.
Sending product announcements from partners by e-mail to new customers

D.
Notifying a customer by e-mail when a product is shipped