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 uterine prolapse, decubitus ulcer in the cervix is caused by : \nSelect and explain. \nA. Friction, B. Malignant change, C. Venous congestion, D. Trophic changes', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Venous congestion', 'role': 'assistant'}]