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': 'What poisoning retards putrefaction : \nSelect and explain. \nA. Phosphorus, B. Arsenic, C. Mercury, D. Lead', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Arsenic', 'role': 'assistant'}]