This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Adrenal Gland, Subject name: Medicine
What is the drug of choice for management of hypeension in Pheochromocytoma? 
Select and explain. 
A. Phenoxybenzamine, B. Phentolamine, C. Labetalol, D. Esmolol
A: Phenoxybenzamine
Answer: A: Phenoxybenzamine 
Explanation: Preoperative patient preparation is essential for safe surgery. a- Adrenergic blockers (Phenoxybenzamine) should be initiated at relatively low doses (e.g. 5-10 mg orally three times per day) and increased as tolerated every few days. Adequate alpha blockade generally requires 7 days, with a typical final dose of 20-30 mg phenoxybenzamine three times per day.