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: ENT
[{'content': "Surfer's ear is \nSelect and explain. \nA. Exostosis, B. Otosclerosis, C. Otitis externa, D. Squamous cell Ca", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]