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': 'The corneal receives all its nutrition from \nSelect and explain. \nA. Corneal vessels, B. Atmosphere, C. Iris, D. All', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Atmosphere', 'role': 'assistant'}]