This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification and metabolism of amino acids, Subject name: Biochemistry
[{'content': 'Most specific marker of pheochromocytoma: \nSelect and explain. \nA. VMA, B. Catecholamine, C. 5 - HIAA, D. Serotonim', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Pheochromocytoma - tumor for Adrenal gland which secretes high amount of epinephrine & Nor-epinephrine catabolic products of catecholamine - VMA VMA can be measured in 24 hours urine sample', 'role': 'assistant'}]