Which strategy is NOT an example of price discrimination?
a a lower price charged for an airline ticket to Chicago purchased three weeks in advance than to a business traveler who bought her ticket the day of the flight and willnot stay overnight
b a Presidents Day sale
c a coupon downloaded from the Internet offering a 10% discount on clothing at Macy's
d a higher price for football tickets on the 50-yard line than for tickets at the back of the end zone