This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'Which of the following is not a calcium channel blockers \nSelect and explain. \nA. Enalapril, B. Nifedipine, C. Verapamil, D. Diltiazem', 'role': 'user'}, {'content': "Answer: A \nExplanation: Refer kDT 7/e p562 Calcium channel blockers are prescription medications that relax blood vessels and increase the supply of blood and oxygen to the hea while also reducing the hea's workload. Examples of calcium channel blockers include: Amlodipine (Norvasc)", 'role': 'assistant'}]