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': 'Phlyctenular keratoconjunctivitis is due to hypersensitivity to which of the following allergens \nSelect and explain. \nA. Pollen, B. Chemicals, C. Mycobacterium tuberculosis proteins, D. Animal fur', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Phlyctenular keratoconjunctivitis is due to hypersensitivity to endogenous allergens like Mycobacterium tuberculosis proteins and Staphylococcus proteins.', 'role': 'assistant'}]