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: Dental
[{'content': 'At birth, child shows marked convex profile. This is due to: \nSelect and explain. \nA. Protruded maxilla, B. Retruded mandible, C. Large sized maxilla, D. Small sized mandible', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]