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': 'Substance commonly used for tissue preservation commonly is: \nSelect and explain. \nA. Ethyl alcohol, B. Formalin, C. Sodium Chloride, D. Normal Saline', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Formalin', 'role': 'assistant'}]