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': 'Optimal timing of administration of prophylactic antibiotic for surgical patients is \nSelect and explain. \nA. at the induction of anesthesia, B. any time during surgical procedure, C. one hour after induction, D. one hour prior to induction of anesthesia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]