American Airlines has a rewards program that allows members to earn points which can be redeemed for airline tickets. The core elementsa round trip ticket using frequent flyer miles--have come to be expected. If the frequent flyer program works as advertised, American Airlines doesn't earn praise in the eyes of the traveler, who won't rave to friends about how great American is. However, American uses value-addedssuch as 500-mile upgrades or one bag flies freeto increase a customer's level of satisfaction. This example shows all of the following EXCEPT: a. Value-addeds can kept from switching to competitors. b. A marketer can affect a customer's level of satisfaction through value-addeds. c. Companies often compete on the value-addeds. d. A core element usually leads to customer satisfaction