Briana undergoes treatment for drug addiction. After she leaves the clinic, Briana is most likely to stay off drugs if the treatment at the clinic was

a. involuntary (she was ordered to undergo treatment) and a difficult ordeal.
b. involuntary (she was ordered to undergo treatment) and an easy experience.
c. voluntary (she chose to undergo treatment) and an easy experience.
d. voluntary (she chose to undergo treatment) and a difficult ordeal.

Answer: D