John has two hours of free time this evening. He ranked his alternatives, first go to a concert, second go to a movie, third study for an economics exam, and fourth answer his e-mail. What is the opportunity cost of attending the concert for John?
◦ attending a movie
◦ studying for an economics exam
◦ answering his e-mail
◦ attending a movie, studying for an economics exam, and answering his e-mail
◦ going to the concert because that is what John chooses to do