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': 'A factory worker presents with excessive salivation, blue lines on gums, tremors, disturbed personality, insomnia and loss of appetite. The most likely poisoning is: \nSelect and explain. \nA. Mercury, B. Lead, C. Arsenic, D. Phosphorus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Mercury', 'role': 'assistant'}]