This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
[{'content': "The 'decisive period' in preventing wound infections is \nSelect and explain. \nA. 4 hr post incision, B. 12 hr prior to incision, C. 12 hr post incision, D. 48 hr post incision", 'role': 'user'}, {'content': "Answer: A \nExplanation: There is up to a 4-hour interval before bacterial growth becomes established enough to cause an infection after a breach in the tissues, whether caused by trauma or surgery. This interval is called the 'decisive period' and strategies aimed at preventing infection from taking a hold become ineffective after this time period.It is therefore logical that prophylactic antibiotics should be given to cover this periodRef: Bailey and Love 27e pg: 46", 'role': 'assistant'}]