This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Type IV hypersensitivity to Mycobacterium tuberculosis antigen may manifest as – 
Select and explain. 
A. Iridocylitis, B. Polyarteritis nodosa, C. Phlyctenular conjunctivitis, D. Giant cell arteritis
C: Phlyctenular conjunctivitis
Answer: C: Phlyctenular conjunctivitis 
Explanation: Phlyctenular conjunctivitis is type IV hypersensitivity reaction to endogenous allergen (tubercular protein, staphylococcal protein).