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
Nutrition for most of the life of ameloblast derived from 
Select and explain. 
A. Dental Sac, B. Dental Papilla, C. Pulp proper, D. None of the above
A: Dental Sac
Answer: A: Dental Sac 
Explanation: None