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': 'Root completion of primary mandibular lateral incisor tooth occurs at an age of \nSelect and explain. \nA. 2-2 ½ year, B. 1-1 ½ year, C. 3-4 year, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]