A professor stood before his class of twenty senior organicbiology students, about to hand out the final exam. "I want to say that it's been a pleasure teaching you thissemester. I know you've all worked extremely hard and many ofyou are off to medical school after summer. So that no onegets their GPA messed up because they might have beencelebrating a bit too much this week, anyone who would liketo opt out of the final exam today will receive a 'B' for thetest." There was much rejoicing in the class as students got up,walked to the front of the class, and took the professor upon his offer. As the last taker left the room, the professorlooked out over the handful of remaining students and asked,"Anyone else? This is your last chance." One final student rose up and opted out of the final. The professor closed the door and took attendance of thosestudents remaining. "I'm glad to see you believe in yourselves,"he said. "You all get 'A's!"