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 permanent tooth occurs 
Select and explain. 
A. 1-1 ½ year after eruption, B. 2-3 year after eruption, C. 6 months after eruption, D. None of the above
B: 2-3 year after eruption
Answer: B: 2-3 year after eruption 
Explanation: None