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': 'Bitemporal diameter of fetus is: \nSelect and explain. \nA. 10.5, B. 8, C. 11 5, D. 9.5', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 8', 'role': 'assistant'}]