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
Mechanism of action of sodium nitroprusside in cyanide poisoning - 
Select and explain. 
A. Produces methemoglobinemia, B. Increased blood flow to liver, C. Increased blood flow to hea, D. Increased blood flow to kidney
A: Produces methemoglobinemia
Answer: A: Produces methemoglobinemia 
Explanation: Ans. is 'a' i.e., Produces methemoglobinemia o Nitrates generate methaemoglobin which has high affinity for cyanide and forms cyanomethaemoglobin.o Cynomethaemoglobin may again dissociate to release cyanide, therefore, sodium thiosulfate is given to form sod.