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 of the following is primarily a venodilator ? \nSelect and explain. \nA. Hydralazine, B. Minoxidil, C. Nitroprusside, D. Nifedipine', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Nitroprusside o Hydralazine, minoxidil and nifedipine are primarily aeriolar dilators whereas nitroprusside is a mixed aeriolar and venous dilator, therefore best answer here seems to be nitroprusside.", 'role': 'assistant'}]