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: Forensic Medicine
At the age of 9 years, the number of permanent teeth is - 
Select and explain. 
A. 12, B. 16, C. 20, D. 24
B: 16
Answer: B: 16 
Explanation: Number of permanent teeth (between 6-11 years) = (Age in years -5) x 4
So, number of permanent teeth at 9 years = (9-5) x 4 = 16