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': 'Prophylactic antibiotics are most effective during \nSelect and explain. \nA. Decisive period, B. Infection period, C. Latent period, D. Golden period', 'role': 'user'}, {'content': "Answer: A \nExplanation: In the first 4 hours, after a breach in an epithelial surface and underlying connective tissues, there is delay in the mobilisation of host defences. This period is called 'decisive period' and during this period, bacterial colonisation and established infection can begin. It is logical that prophylactic antibiotics will be most effective during this time.", 'role': 'assistant'}]