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
Sodium-nitroprusside acts by activation of: 
Select and explain. 
A. Guanylate cyclase, B. K+ channels, C. Ca++ channels, D. Cyclic AMP
A: Guanylate cyclase
Answer: A: Guanylate cyclase 
Explanation: Ans. (A) Guanylate cyclase(Ref: KDT 8th/e p613)Nitroprusside generates NO that relaxes vascular smooth muscles by activating guanylate cyclase.