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': 'Most sensitive test for diagnosing pheochromocytoma is : \nSelect and explain. \nA. MRI, B. 24 hour urinary xma, C. MIBG scan, D. Plasma free metanephrines', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Plasma free metaneprines is the most sensitive test.\n24 hour urinary VMA is used for screening.\nMRI is the IOC for extraadrenal pheochromocytomos.', 'role': 'assistant'}]