This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Labour - II, Subject name: Gynaecology & Obstetrics
[{'content': 'Commonest diameter of fetal head engagement is \nSelect and explain. \nA. Submentoveritcal, B. Occipito frontal, C. Suboccipito bregmatic, D. Mentoveical', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The commonest diameter for fetal head engagement is suboccipitobregmatic, as it leads to veex presentation for normal vaginal delivery. Fetal skull diameters Measurements Suboccipitobregmatic Biparietal diameter Submentobregmatic 9.5 cm Suboccipitofrontal 10cm Occipitofrontal Submentoveical 11.5 cm Mentoveical 14 cm', 'role': 'assistant'}]