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': 'Diameter of engagement in face presentation is : \nSelect and explain. \nA. Submentobregmatic, B. Submentooccipital, C. Biparietal, D. Bitemporal', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Submentobregmatic', 'role': 'assistant'}]