This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
[{'content': 'Which of the following is most useful for reversing severe ergot induced vasospasm? \nSelect and explain. \nA. Ergotamine, B. Methysergide, C. Nitroprusside, D. Phenoxybenzamine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Nitroprusside is a mixed dilator and is highly effective agent against ergot induced vasospasm. It is also the drug of choice for most of the hypeensive emergencies.', 'role': 'assistant'}]