The statements are not true for allergy:(A) Allergy is due to release…

The correct answer is Option (1) → (C) and (D) only

(A) Allergy is due to release of chemicals like histamine and serotonin — True. Mast cells release them and cause the symptoms.

(B) Allergens are the subtances which cause allergy — True. Dust mites, pollen and animal dander are examples.

(C) The antibodies produced due to allergens are IgA type — False. Antibodies against allergens are of the IgE type. IgA is found in colostrum.

(D) Adrenalin and steroids quickly enhance the symptoms of allergy — False. Antihistamines, adrenalin and steroids quickly reduce the symptoms.

NCERT Extract:
Allergies – “The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are called allergens. The antibodies produced to these are of IgE type. Common examples of allergens are mites in dust, pollens, animal dander, etc. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. Allergy is due to the release of chemicals like histamine and serotonin from the mast cells. For determining the cause of allergy, the patient is exposed to or injected with very small doses of possible allergens, and the reactions studied. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy.”