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
Most specific marker of pheochromocytoma: 
Select and explain. 
A. VMA, B. Catecholamine, C. 5 - HIAA, D. Serotonim
A: VMA
Answer: A: VMA 
Explanation: 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