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': 'The given procedure is used to diagnose \nSelect and explain. \nA. Vesicovaginal fistula, B. Urethral diverticula, C. Stop post - partum hemorrhage, D. Pelvic organ prolapse', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Trattner - double balloon catheter is used to diagnose urethral diverticula.', 'role': 'assistant'}]