Egan Is Unable to Swim, and the Other Kids in His

Egan is unable to swim, and the other kids in his camp troop regularly tease him for this deficit. He finds that when he tries to swim, the kids respect his courage and stop mocking him. In a short amount of time, he is swimming like a champ, and the teasing completely stops. In this case, the cessation of the teasing is an example of

A) positive reinforcement.
B) penalty.
C) negative reinforcement.
D) positive punishment.