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': 'Phlicten is due to: \nSelect and explain. \nA. Exogenous allergy, B. Endogeneous allergy, C. Viral keratitis, D. Fungal keratitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Endogenous allergy', 'role': 'assistant'}]