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': 'Which of the following urinary metabolites are most sensitive for diagnosis of pheochromocytomas \nSelect and explain. \nA. VMA, B. Metanephrines, C. 5HIAA, D. 5HTP', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Answer is B (Metanephrines): The most sensitive test for diagnosis of pheochromocytomas is measurement of fractionated metanephrines in urine and free metanephrines in plasma.', 'role': 'assistant'}]