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
Root completion of Mandibular Lateral incisor tooth occurs at an age of 
Select and explain. 
A. 9-10 year, B. 3-4 year, C. 12-13 year, D. None of the above
A: 9-10 year
Answer: A: 9-10 year 
Explanation: None