This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: CHF, Angina Pectoris and Myocardial Infarction, Subject name: Pharmacology
[{'content': 'Which of the following drugs is both aeriolar and venodilator? \nSelect and explain. \nA. Hydralazine, B. Sodium nitroprusside, C. Minoxidil, D. Nitroglycerine', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Group Effect in CHF Drugs Predominant aeriolar dilator Decrease afterload Hydralazine Predominant venodilator Decrease preload Nitrates Mixed dilator Decrease both preload and afterload Nitroprusside', 'role': 'assistant'}]