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
Which of the following structures is not of ectodermal origin: 
Select and explain. 
A. Hunter-schreger bands, B. Enamel spindles, C. Enamel tufts, D. Enamel lamellae
B: Enamel spindles
Answer: B: Enamel spindles 
Explanation: Enamel spindles are odontoblastic process, which extend into enamel. Enamel spindles are mesenchymal in origin.