This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Ophthalmology
[{'content': 'Critical angle of air corneal interface- \nSelect and explain. \nA. 36 degree, B. 46 degree, C. 56 degree, D. 66 degree', 'role': 'user'}, {'content': 'Answer: B \nExplanation: *Critical angle of cornea-air interface is, approximately 46o. Ref: Khurana: Theory and practice of refraction 7th/e p.99', 'role': 'assistant'}]