This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological diagnosis and operative surgery, Subject name: Gynaecology & Obstetrics
[{'content': 'Position of the patient should be as described except \nSelect and explain. \nA. Diagnostic laparoscopy- trendlelnburg with about 30 degree tilt, B. Colposcopy - Lithotomy, C. Transvaginal sonography in Gynecology - Lithotomy with full bladder, D. Hysteroscopy - Lithotomy', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Bladder should be empty during a transvaginal ultrasound', 'role': 'assistant'}]