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': 'After vasectomy aspermia will become evident in: \nSelect and explain. \nA. 2 to 3 weeks, B. 4 to 6 weeks, C. 8 to 10 weeks, D. 10 to 12 weeks', 'role': 'user'}, {'content': 'Answer: D \nExplanation: 10 to 12 weeks', 'role': 'assistant'}]