Professor Emerson needs to talk

The class soon ended and everybody began to walk out. As John stopped to exit the classroom, Professor Emerson spoke up. "John, wait a minute. We need to talk."

"Professor, I need to get to my next class...assuming of course there is a next class," he replied.

"This won't take a moment," she promised him. "I just want to talk about your grades."

John stopped, his heart sinking. He thought he was doing well in the class, but the way she talked...

"Don't worry. Your grades are great. In fact, you would still get an A even if you failed or didn't take the final. I was just wondering if you would like to earn some extra credit, though."

John was wary. "What kind of extra credit?"

She replied, "Meet me at...