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': 'A dead body is having cadaveric lividity of bluish green colour. The most likely cause of death is by poisoning due to - \nSelect and explain. \nA. Hydrocyanic acid, B. Hydrogen sulphide, C. Ocleander, D. Sodium nitrite', '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, Chapter 35.", 'role': 'assistant'}]