Loperamide (Brand Name: Imodium),which Is Available on an Over-The-Counter Basis,does

Multiple Choice

Loperamide (brand name: Imodium) ,which is available on an over-the-counter basis,does not produce any psychoactive effects if/because __________.

A) it is used by heroin addicts
B) it is taken in moderation
C) it is a licit drug
D) it cannot cross the blood-brain barrier