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: Pharmacology
Which of the following is not given alone in a patient of pheochromocytoma ? 
Select and explain. 
A. Atenolol, B. Prazosin, C. Nitroprusside, D. Metyrosine
A: Atenolol
Answer: A: Atenolol 
Explanation: None