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': 'Carcinoma cervix involving upper 2/3rd of vagina. The stage would be: September 2009 \nSelect and explain. \nA. Stage II a, B. Stage II b, C. Stage III a, D. Stage III b', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A: Stage II a', 'role': 'assistant'}]