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': 'Critical obstetric conjugate for trial of labour is: \nSelect and explain. \nA. 8.5 cms, B. 9.0 cms, C. 9.5 cms, D. 10.0 cms', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]