Johnny Was Playing on His Swing Set When a Semi

Multiple Choice

Johnny was playing on his swing set when a semi truck blasted its horn on the street directly in front of him.Johnny was so startled that he fell off the swing and skinned his knee.Now Johnny gets scared every time he hears a truck.This is an example of:

A) punishment.
B) classical conditioning.
C) negative reinforcement.
D) operant conditioning.