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': "A case of vasectomy is said to have failed as the vasectomised person's wife gives bih to a child ten months after the operation. Which one of the following is the most probable cause : \nSelect and explain. \nA. Failure of the husband to use a condom after vasectomy, B. Surgical failure, C. Recanalisation, D. Wife had extra -- marital contact", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Failure of the husband to use a condom after vasectomy', 'role': 'assistant'}]