Tylenol and Advil Are Two Brands of Over-The-Counter Products for Ailments

Tylenol and Advil are two brands of over-the-counter products for ailments such as colds, headaches, sore throats, arthritis aches, and general pain and fever. Their manufacturers seek distribution of these products through drugstores such as Walgreens and CVS that have many options for customer, satisfying a buyer's desire for

A) variety.
B) information.
C) pre-or postsale service.
D) convenience.
E) adaptability.