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': 'ln multiparous women, external os is i \nSelect and explain. \nA. Circular, B. Longitudinal, C. Transverse, D. Septate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Transverse', 'role': 'assistant'}]