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 6 years of age, the Lengthening of mandible occurs mainly \nSelect and explain. \nA. at the symphysis, B. between the canines, C. Distal to first permanent molar, D. Along the lower border', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]