Erick is an employee of Hilton Hotels Inc.in Washington, DC. On his vacation, Erick travels to Boston and stays at a Hilton Hotel for six nights free of charge. The regular rate for a hotel room at Hilton in Boston is $400 a night. Hilton usually earns $100 per hotel room per night as profit. His ability to stay in the hotel without charge is based on the availability of empty rooms. How much income must Erick report due to the use of the Boston hotel room? Select one: a. $2,400 b. $600 c. $0 d. $1920