The correct answer is C. Antihistamine
Explanation:
Allergies occur as the immune system of an individual reacts to a substance such as dust, pollen, or specific food triggering an inflammatory reaction. Additionally, one of the chemicals in the body that is involved in this excessive reaction is the histamine as this chemical increases when individuals are in contact with allergens, and leads to symptoms such as skin rash or red eyes. In this context, to stop an allergic response the best is an antihistamine because this stops or reduces the action of histamine and therefore would reduce the symptoms Amy is experiencing.