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
Among the following, the structure that is most calcified is 
Select and explain. 
A. Enamel lamella, B. Enamel rod, C. Enamel spindle, D. Enamel tuft
B: Enamel rod
Answer: B: Enamel rod 
Explanation: None