【单选题】Company Alpha buys free-travel coupons from people who are awarded the coupons by Bravo Airlines for flying frequently on Bravo airplanes. The coupons are sold to people who pay less for the coupons t...
A.
number of coupons that a person can be awarded in a particular year.
B.
use of the coupons to those who were awarded the coupons and members of their immediate families.
C.
days that the coupons can be used to Monday through Friday.
D.
amount of time that the coupons can be used after they are issued.
E.
number of routes on which travelers can use the coupons.