This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pharmacology
[{'content': 'The mechanism of action of sodium nitroprusside is: \nSelect and explain. \nA. Increased cAMP, B. Stimulation of guanylate cyclase, C. Calcium channel blockage, D. K+ channel opener', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (B) Stimulation of guanylate cyclase(Ref: KDT 8th/e p544)Sodium nitroprusside acts by releasing nitric oxide (NO). This stimulates guanylate cyclase and results in the elevation of cGMP, which is a potent vasodilator.', 'role': 'assistant'}]