This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Bandle ring on uterus suggests \nSelect and explain. \nA. Cervical dystocia, B. Cochleate uterus, C. Hypeonic uterus, D. Obstructed labour', 'role': 'user'}, {'content': "Answer: D \nExplanation: In Tonic Uterine Contraction and Retraction, a circular groove encircling the uterus is formed between the active upper segment and the distended lower segment, called pathological retraction ring (Bandl's ring). Reference: D C Dutta Textbook of Obstetrics 7th edition page 362", 'role': 'assistant'}]