The U.S. Postal Service now offers a "Click-N-Ship" online service, where users can buy and print postage and labels online. According to the "Buyer Utility Map," the U.S. Postal Service is offering the _____ utility lever, during the _____ stage of buyer experience cycle.
A. risk, use
B. fun and image, maintenance
C.convenience, purchase
D. environmental friendliness, disposal