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': 'After the age of six the increase in the size of mandible\noccurs at: \nSelect and explain. \nA. Symphysis, B. Between canines, C. Along the lower border, D. Distal to 1st molars', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]