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': 'The MOST sensitive 24 hour urinary biochemical test to suggest pheochromocytoma among the following is \nSelect and explain. \nA. Vanillylmandelic acid, B. Fractionated metanephrines, C. Total metanephrines, D. Catecholamines', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Table 343-2 Biochemical Tests Used for Pheochromocytoma Diagnosis Diagnostic Method Sensitivity Specificity 24-h urinary tests Vanillylmandelic acid ++ ++++ Catecholamines +++ +++ Fractionated metanephrines ++++ ++ Total metanephrines +++ ++++ Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 2963', 'role': 'assistant'}]