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
Extension of odontoblast processes into enamel 
Select and explain. 
A. Enamel spindle, B. Cracks, C. Primary dentin, D. Secondary Dentine
A: Enamel spindle
Answer: A: Enamel spindle 
Explanation: Enamel spindle-

Diameter (2p)
Extended odontoblast processes in enamel
Perpendicular (right angle) to dentin
DDT (Dark - Dehydrated - Transmitted light)