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
Bright red color on postmortem staining found in – 
Select and explain. 
A. CO, B. P, C. H2S, D. HCN
D: HCN
Answer: D: HCN 
Explanation: The colour of postmortem hypostasis in HCN poisoning is bright red due to impaired oxygenation of tissues and formation of cyanmethhemoglobin.