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': 'Involvement of pelvis in a case of vaginal carcinoma of stage: \nSelect and explain. \nA. I, B. II, C. III, D. IV', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]