The correct option is A Antihistamines
Antihistamines are drugs which treat allergic rhinitis and other allergies. Antihistamines can give relief when a person has nasal congestion, sneezing, or hives because of pollen, dust mites, or animal allergy. Typically people take antihistamines as an inexpensive, generic, over-the-counter drug with few side effects. As an alternative to taking an antihistamine, people who suffer from allergies can instead avoid the substance which irritates them. However, this is not always possible as some substances, such pollen, are carried in the air, thus making allergic reaction caused by them generally unavoidable.