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 index age group for deciduous teeth in year is: 
Select and explain. 
A. 12, B. 5, C. 35 - 44, D. 65 - 74
B: 5
Answer: B: 5 
Explanation: None