This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Gynaecology & Obstetrics
[{'content': 'Smallest pelvic diameter is \nSelect and explain. \nA. True conjugate, B. Interspinous diameter, C. Inteuberous diameter, D. Posterior sagittal diameter', 'role': 'user'}, {'content': "Answer: B \nExplanation: The interspinous diameter is 10 cm or slightly greater, is usually the smallest pelvic diameter, and, in cases of obstructed labor, is paicularly impoant.(Ref: William's Obstetrics; 25th edition)", 'role': 'assistant'}]