This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Forensic Medicine
[{'content': 'Red brown post moem staining is seen in - \nSelect and explain. \nA. Dhatura, B. Aniline, C. CO, D. Nitrites', 'role': 'user'}, {'content': "Answer: B \nExplanation: Poison Color Nitrites Reddish brown Potassium chlorate Chocolate brown Phosphorus Dark brown Hydrogen sulphide Bluish green Cyanide Cherry red Carbon monoxide Pink Opium Blackish Ref: K.S.Narayan Reddy's Synopsis of Forensic Medicine and Toxicology , 29th edition.", 'role': 'assistant'}]