Which of the following best illustrates the concept of negative reinforcement?

A) A man ingests an aspirin to rid himself of a strong headache.
B) A woman injects heroin into her veins to obtain a "rush."
C) A rat presses a lever that results in delivery of shock through the floor of the chamber.
D) A hungry rat presses a lever to obtain a food pellet.
E) A child is sent to his room after screaming at the dinner table.

Answer: A
Rationale: The concept of negative reinforcement is illustrated by the example in which a man ingests an aspirin to rid himself of a strong headache.