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 percentage of inorganic matter in fully developed enamel is about 
Select and explain. 
A. 66%, B. 76%, C. 86%, D. 96%
D: 96%
Answer: D: 96% 
Explanation: Enamel contains 96% of inorganic material and 4% of organic material. The inorganic material is mainly composed of hydroxyappatite crystals.