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
Average duration of function of primary dentition 
Select and explain. 
A. 6 years, B. 8 years, C. 10 years, D. 12 years
A: 6 years
Answer: A: 6 years 
Explanation: Average duration of function of primary dentition is 6 yrs while maximum duration is 10 years.