Which of the following is a policy a store can adopt to make low-profit customers more profitable?
A. 2Wheels sends birthday greetings to its best customers and gives them discounts on merchandise.
B. 2Wheels has a club for its regular customers, organizing cycling events and parties for them.
C. Though 2Wheels previously offered free delivery, it now charges for deliveries made outside the city.
D. 2Wheels allows existing customers to upgrade to a newer model at less than the sticker price by trading in their older model.
E. 2Wheels encourages customers to send in their suggestions for product improvement.