This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
[{'content': 'Which of the following is a pro drug? \nSelect and explain. \nA. Hydralazine, B. Clonidine, C. Captopril, D. Enalapril', 'role': 'user'}, {'content': 'Answer: D \nExplanation: ACEI inhibitors are all prodrugs except captopril and ramipril. hydralazine is an aeriolar dilator enalapril is an ACEI inhibitor used in hypeensive emergencies. Ref: KDT 6/e pg 20.', 'role': 'assistant'}]