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: Social & Preventive Medicine
[{'content': 'A case of vasectomy is said to have failed as the vasectomised person’s wife gives birth to a child ten months after the operation. Which one of the following is the most probable cause? \nSelect and explain. \nA. Surgical failure, B. Failure of the husband to use condom after vasectomy, C. Recanalisation, D. Wife had extramarital contact', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]