This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Labour - normal, abnormal, malposition, malpresentation and their management, Subject name: Gynaecology & Obstetrics
[{'content': 'Transverse diameter of the pelvic outlet is: \nSelect and explain. \nA. 9.5 cm, B. 10.5 cm, C. 11.5 cm, D. 12.5 cm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Transverse diameter of the obstetrical outlet / inter-ischial tuberous diameter - 10.5 cm An inter-ischial tuberous diameter of 8 cm or less is defined as a Contracted Outlet', 'role': 'assistant'}]