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': 'Acts both as poison and antidote: NEET 13 \nSelect and explain. \nA. Copper sulfate, B. Mercuric chloride, C. Silver chloride, D. Thallium arsenate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. Copper sulfate', 'role': 'assistant'}]