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': 'Phlycten is due to – \nSelect and explain. \nA. Exogenous allergy, B. Endogeneous allergy, C. Viral keratitis, D. Fungal keratitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Phlyctenular conjunctivitis → Endogenous allergy\nVernal keratoconjunctivitis →\xa0\xa0\xa0\xa0 Exogenous allergy', 'role': 'assistant'}]