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: Surgery
[{'content': 'Gold standand for diagnosis of carotid body tumour is \nSelect and explain. \nA. Duplex scanning, B. MRI, C. Computed Tomography, D. Cerebral angiography', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]