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': 'The shoest diameter of fetal skull is : \nSelect and explain. \nA. Sub occipito frontal, B. Sub mentobregmatic, C. Mento veical, D. Submentoveical', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sub mentobregmatic', 'role': 'assistant'}]