A patient at a sports camp is complaining of itchy and watery eyes, coughing, and sneezing when outdoors. The patient's chart states that he has an allergy to grasses. Which medication will the nurse administer?

A. Antihistamine: Antihistamines are the first-line treatment for allergic reactions such as itchy, watery eyes, sneezing, and coughing caused by allergens like grass pollen. They block histamine, the chemical responsible for allergic symptoms, providing effective relief in seasonal allergies. B. Antitussive: Antitussives suppress coughing and are used for dry, nonproductive coughs. They do not address the underlying allergic reaction or associated symptoms like sneezing and itchy eyes, making them inappropriate for this case. C. Decongestant: Decongestants relieve nasal congestion by constricting blood vessels in the nasal mucosa. While they may help with stuffiness, they do not treat the histamine-mediated symptoms such as watery eyes or sneezing effectively. D. Expectorant: Expectorants thin mucus to help with productive coughs. They are not helpful in treating allergic reactions and will not relieve the patient's symptoms caused by grass allergy exposure.