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
Korffs fibres are seen in: 
Select and explain. 
A. Mantle dentin, B. Secondary dentin, C. Reactionary dentin, D. Indeed dermal tubules
A: Mantle dentin
Answer: A: Mantle dentin 
Explanation: None