For several years, a professor at Johns Hopkins University had been using the following grading scheme for his final exam: He would give an A to the student with the highest score. The grades of the remaining students were then based on what percentage their scores were of the top student's score.

In the fall of 2012, the students in the class came up with the idea of boycotting the final exam. They stood in the hallway outside the classroom but did not enter the room to take the exam. After waiting for a time, the professor cancelled the exam and, applying his grading scale, gave everyone in the class an A on the exam. An article in the New York Times about this incident observes: "This is an amazing game theory outcome, and not one that economists would likely predict."

Game theory indicates the students' strategy was unlikely to work because

a. game theory predicts that there must be winners and losers.
b. it is difficult to get a group of people to agree and not defect.
c. it is a violation of university policy to refuse to take an exam.
d. game theory is predicated on Nash equilibriums.