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': 'True about isthmus are all except : \nSelect and explain. \nA. Measures 20 mm in length, B. Forms lower uterine segment, C. Mucosa similar to endometrium, D. Present between cervical mucosa and endometrial mucosa', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Measures 20 mm in length', 'role': 'assistant'}]