Correct Option: B

Hay fever involves an allergic reaction to pollen. A similar reaction occurs with allergy to mold, animal dander, dust, and other allergens that you breathe in. Allergic rhinitis is a group of symptoms affecting the nose. These symptoms occur when you breathe in something you are allergic to, such as dust, dander, insect venom, or pollen. An allergen is something that triggers an allergy. When a person with allergic rhinitis breathes in an allergen such as pollen or dust, the body releases chemicals, including histamine.