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
[{'content': 'Bright red color on postmortem staining found in - \nSelect and explain. \nA. CO, B. HCN, C. H2S, D. P', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In cyanide (HCN) poisoning, postmortem staining is pink or bright red.', 'role': 'assistant'}]