Suppose You Are an Experimenter, and You Have Trained Someone

Suppose you are an experimenter, and you have trained someone to press a lever to avoid shocks. Now you disconnect the shock generator. Other than telling the person what you have done, what procedure would be most successful in facilitating extinction of the lever pressing?

A) Sound a mild buzzer each time an avoidance response was made.
B) Reconnect the shock generator and increase the shock intensity.
C) Keep the person out of the experimental setting for a few days.
D) Prevent the person from pressing the lever.