Your Classmates from the University of Chicago Are Planning to Go

Your classmates from the University of Chicago are planning to go to Miami for spring break, and you are undecided about whether you should go with them. The round-trip airfare is $600, but you have a frequent-flyer coupon worth $500 that you could use to pay part of the airfare. All other costs for the vacation are exactly $900. The most you would be willing to pay for the trip is $1,400. Your only alternative use for your frequent-flyer coupon is for your trip to Atlanta two weeks after the break to attend your sister's graduation, which your parents are forcing you to attend. The Chicago-Atlanta round-trip airfare is $450. What is the opportunity cost of using the coupon for the Miami trip?

A) $100
B) $450
C) $500
D) $550