This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
[{'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 condom after vasectomy, B. Surgical failure, C. Recannalisation, D. Wife had extramarital contact', 'role': 'user'}, {'content': 'Answer: B \nExplanation: <p> Surgical failure is the reason . Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:509. <\\p>', 'role': 'assistant'}]