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: Medicine
[{'content': 'A person has headache & profuse sweating. On examination his B.P is 200/120 mm Hg. Which of the following shoud not be used -a) Nifedipineb) Phenoxybenozamine c) Methyldopad)  Labetalol \nSelect and explain. \nA. ab, B. abc, C. bc, D. bd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]