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': 'The mean value of APDI in normal occlusion is: \nSelect and explain. \nA. 78.4 ± 3.79, B. 81.4 ± 13.79, C. 89.3 ± 4.79, D. 91.2 ± 3.27', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]