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
Ionic exchange between enamel surface and environment: 
Select and explain. 
A. Does not take place once enamel matures, B. Stops after 2 years of eruption, C. Continues till adult life, D. Continues through out life
D: Continues through out life
Answer: D: Continues through out life 
Explanation: None