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': "Bandle's ring on the uterus in labour suggests: \nSelect and explain. \nA. Cervical dystocia, B. Colicky uterus, C. Hypeonic lower uterine segment, D. Obstructed labour", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Obstructed labour', 'role': 'assistant'}]