According to the Postal Reorganization Act of 1970, any unsolicited merchandise sent by mail is free to be used at the recipient’s discretion, ________

a. unless the Inspector General of the United States Postal Service (U.S.P.S.) requires the merchandise to be returned
b. with no obligation owed by the recipient to the sender
c. but she must pay the shipping expenses
d. unless the merchandise has a value of over $1,000
e. unless the merchandise has a value of over $500