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
Ameloblasts are derived from: 
Select and explain. 
A. Inner enamel epithelium., B. Outer enamel epithelium., C. Reduced enamel epithelium., D. All of the above.
A: Inner enamel epithelium.
Answer: A: Inner enamel epithelium. 
Explanation: Enamel organ is derived from the inner enamel epithelium of the enamel organ.