This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Anatomy
[{'content': 'The shoest diameter of fetal head : \nSelect and explain. \nA. Biparietal diameter, B. Suboccipitofrontal diameter, C. Occipitofrontal diameter, D. Bitemporal diameter', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Bitemporal and biparietal diameters are transverse diameters whereas suboccipitofrontal and occipitofrontal are the anteroposterior diameters Bitemporal diameter is 8 cm Ref: Datta Obs 9e pg 77.', 'role': 'assistant'}]