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: Anatomy
[{'content': 'The pneumatisation process in maxillary sinus completes in? \nSelect and explain. \nA. 6-8 years, B. 13-14 years, C. 8-10 years, D. 18-20 years', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]