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
Calcification of third molar begins at: 
Select and explain. 
A. 8 months, B. 18 months, C. 8 years, D. 16 years
C: 8 years
Answer: C: 8 years 
Explanation: None