This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
Investigation of choice in pheochromocytomais- 
Select and explain. 
A. CTscan, B. Urinary catecholamines, C. MlBGscan, D. Urinary calcium measurement
B: Urinary catecholamines
Answer: B: Urinary catecholamines 
Explanation: Pheochromocytoma synthesize and store catecholamines. Elevated plasma and urinary levels of catecholamines are impoant for diagnosis Ref -( Harrison 17 pg 2270)