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': 'Which antihypertensive is a prodrug and is converted to its active form in the brain? \nSelect and explain. \nA. Clonidine, B. Methyldopa, C. Minoxidil, D. Nitroprusside', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]