If an Endorser Is Represented as an Actual User of the Marketer's

If an endorser is represented as an actual user of the marketer's product, the endorsement can only be used as long as:

A) the endorser is given free samples to distribute to others.
B) the endorser does not use a rival's products.
C) the endorser is seen with the product in public.
D) the endorser continues to use the product.
E) the endorser purchases the product at least once in three months.