This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Note a delayed type of hypersensitive reactions - 
Select and explain. 
A. Contact dermatitis, B. Bronchial asthma, C. Hemolytic anemia, D. Multiple sclerosis
A: Contact dermatitis
Answer: A: Contact dermatitis 
Explanation: Cntact dermatitis is a type IV hypersensitivity reaction. - delayed hypersensitivity sometimes results results from skin contact with a variety of chemicals Metals such as nickel and chromium, simple chemicals like dyes,drugs or plant allergens. The antigen activates specifically sensitised CD4 & CD8 T lymphocytes leading to the secretion of lymphokines and phagocyte accumulation. Reference : Anathanarayan & paniker's 9th edition, pg no: 162,167 <\p>