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, fever, and general pain. Both of their manufacturers seek distribution of their products through pharmacies such as Walgreens and CVS. These companies seek channels and intermediaries that will satisfy a buyer's desire for

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