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: Medicine
[{'content': 'Investigation of choice in pheochromocytoma is - \nSelect and explain. \nA. CT scan, B. Urinary catecholamines, C. MIBG scan, D. Urinary calcium measurement', 'role': 'user'}, {'content': "Answer: B \nExplanation: Diagnosis of pheochromocytoma\xa0:-\n\nThe diagnosis is typically confirmed by measurement of urinary and plasma fractionated metanephrines and catecholamines.\nHowever there are major regional institutional and international differences in the approach to the biochemical diagnosis of pheochromocytoma and there is still no consensus as to the 'best test'.\nHistorically, many institutions relied upon measurement of 24 hour urinary excretion of catecholamines and total metanephrines.\n\n- Move recently plasma fractionated metanephrines has been proposed by some investigators as superior test. \n\xa0- Now days the diagnostic test is based upon the patients clinical presentation.", 'role': 'assistant'}]