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': 'In which one of the following conditions is sling operation done : \nSelect and explain. \nA. Multiple prolapse, B. Nulliparous prolapse, C. Cystocoele, D. Rectocoele', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Nulliparous prolapse', 'role': 'assistant'}]