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: Gynaecology & Obstetrics
[{'content': 'The bladder should be empty within : \nSelect and explain. \nA. 2-3 hrs of delivery, B. 3-4 hrs of delivery, C. 4-5 hrs of delivery, D. 6-8 hrs of delivery', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 3-4 hrs of delivery', 'role': 'assistant'}]