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
Following eruption, the root of the maxillary central incisor completes development at what approximate age? 
Select and explain. 
A. 7 years, B. 8 years, C. 9 years, D. 10 years
D: 10 years
Answer: D: 10 years 
Explanation: None