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': 'Bolton analysis is used to determine \nSelect and explain. \nA. Arch length - tooth size discrepancy, B. Apical base Length to arch perimeter, C. Tooth size ratio in maxilla, D. Upper teeth to lower teeth size ratio', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]