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: Surgery
[{'content': 'Which among the following is commonly used as a preservative for gut sutures: \nSelect and explain. \nA. Isopropyl alcohol., B. Saline., C. Formocresol., D. Ethyl alcohol.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]