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: Forensic Medicine
A dead body with suspected poisoning is having hypostasis of red brown or deep blue in colour. It is suggestive of poisoning due to- 
Select and explain. 
A. Nitrates, B. Carbon monoxide, C. Cyanides, D. Barbiturates
A: Nitrates
Answer: A: Nitrates 
Explanation: None