Getting A's

The professor stood before his class of senior biology students, about to hand out the final exam.
"I want to say that it's been a pleasure teaching you this semester.
I know you've all worked extremely hard and many of you are off to
medical school after the summer. I don't want anyone to get their GPA messed up
because they might have been celebrating a bit too much this
week, so anyone who would like to opt out of the final exam now
will receive a 'B' for the course."

Naturally, there was much rejoicing in the class as students got
up, walked to the front of the class and took the professor up
on his offer.

As the last taker left the room, the professor looked 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 those
students remaining. "I'm glad to see you believe in yourself,"
he said. "You all get 'A's."