This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': 'The investigation of choice for extra-adrenal pheochromocytoma \nSelect and explain. \nA. CT, B. MRI, C. X-ray, D. MIBG scan', 'role': 'user'}, {'content': 'Answer: A \nExplanation: MIBG scan is useful for extra-adrenal pheochromocytoma but IOC is MRI even for extra-adrenal pheochromocytoma', 'role': 'assistant'}]