This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glaucoma, Subject name: Ophthalmology
[{'content': 'The critical angle of cornea-air interface is: \nSelect and explain. \nA. 36o, B. 46o, C. 56o, D. 66o', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Cornea air interface is 46 degree.', 'role': 'assistant'}]