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
The number of sites examined to assess the stages of bone maturation in Fishman's skeletal maturation index are: 
Select and explain. 
A. 4, B. 5, C. 6, D. 7
C: 6
Answer: C: 6 
Explanation: None