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
[{'content': 'All of the following are useful in the intravenous therapy for hypertensive emergencies except: \nSelect and explain. \nA. Fenoldopam, B. Urapidil, C. Enalaprilat, D. Nifedipine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]