You have been called to a residence for a female patient who awoke with swollen lips and a rash to her arms and abdomen. In addition, she exhibits a mild expiratory wheeze in all lung fields. She states that she called her doctor who advised her to take some Benadryl and call 911 for emergency care. How will the Benadryl, acting as an antihistamine, benefit the patient?

A) It helps her immune system to deactivate the allergen.
B) It acts as an allergen to stop the allergic reaction.
C) It stops the constriction of the patient's small airways.
D) It dilates her blood vessels and delivers more blood to the brain.

C