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
Non acidic, nonionic protein which helps in enamel mineralization 
Select and explain. 
A. Tuftelin, B. Sheathlin, C. Enamelin, D. Amelogenin
D: Amelogenin
Answer: D: Amelogenin 
Explanation: None