This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genital Prolapse - various presentation of prolapse and management of urinary stress incontinence (I am hanging by my nails !), Subject name: Gynaecology & Obstetrics
[{'content': 'The most common cause of vesicovaginal fistula(VVF) in under-developed countries would be: \nSelect and explain. \nA. Obstetrical injury, B. Pelvic irradiation, C. Carcinoma, D. Haemorrhoidectomy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Causes of vesico vaginal fistula: Gynaecological Surgery: Most common cause in developed countries Obstetric injury/ Obstructed labour (leading to tissue necrosis): Most common cause in developing countries Radiation Malignancy Foreign bodies: forgotten pessaries Direct trauma Infective: TB, schistosomiasis, syphilis, LGV Endometriosis, perforating bladder calculi', 'role': 'assistant'}]