Every time Beth buys a book at Waldenbooks, she presents her Waldenbooks card, and the sales associate enters her purchase in a database. When she has purchased five books at regular price, she is sent a coupon for a free book to be picked out on her next visit to the store. This is an example of a:
A. bonus program.
B. frequency program.
C. customer rewards contest.
D. self-liquidating promotion.
E. subsidized program.
Answer: B