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 transitory structures that may be seen during early tooth development are 
Select and explain. 
A. Enamel Knot, B. Enamel Navel, C. Enamel Cord, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: None