Which one is the correct example of a kickback?

A. Amy understates her company's unearned revenue to make the total revenue look more impressive

B. Amy gives her hardware salesman tickets to the football game. In exchange, the salesman gives her an unfairly low price on hardware.

C. A customer buys a CD Player, but Amy doesn't record the transaction, she keeps the money for herself.

D. Wyatt ate only cheap sandwiches during his business trip, but he claimed over $100 in food expenses to his company.