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
[{'content': 'Type IV hypersensitivity to Mycobacterium tuberculosis antigen may manifest as – \nSelect and explain. \nA. Iridocylitis, B. Polyarteritis nodosa, C. Phlyctenular conjunctivitis, D. Giant cell arteritis', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Phlyctenular conjunctivitis is type IV hypersensitivity reaction to endogenous allergen (tubercular protein, staphylococcal protein).', 'role': 'assistant'}]