The Entertainment Book Is Jammed with Discounts on Dining,travel,and Entertainment

The Entertainment Book is jammed with discounts on dining,travel,and entertainment provided by both local and national businesses.It was created by Entertainment Publications over 30 years ago.People are so excited about good,cheap fun that they're willing to pay between $40 and $50 for the book.Consumers justify the cost because total values offered in any Entertainment Book are worth hundreds of dollars.And as the books grow in popularity,more marketers are requesting that a coupon for their businesses be featured in the book.Over 5 million copies of the book are sold each year,and sales are growing steadily.In all,more than 100,000 merchants,including 40,000 restaurants,are represented in the Entertainment Book,making it the largest national discount dining program.Further,the Entertainment Book is sold through clubs,youth groups,and schools.Entertainment Publications creates and distributes ads,posters,and other sales materials to all its sales organizations.Entertainment Publications has teamed up with Esso to provide a premium item called the MultiCard Savings Book.Esso distributes the book to all its MultiCard members.It contains local and national advertisers that are of interest to Esso members.In a joint venture with American Airlines,Entertainment Publications created a program called Advantage Dining,which was offered to the airline's frequent flyer customers as another way to earn miles.
-Refer to The Entertainment Book.What did Esso use to enhance its relationships with its customers?

A) rebates
B) coupons
C) premiums
D) trade allowances