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': 'Clinically vesicovaginal and ureterovaginal fistula are differentiated by : \nSelect and explain. \nA. USG, B. IVP, C. Cystoscopy with dye, D. Methylene blue three swab test', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Methylene blue three swab test', 'role': 'assistant'}]