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
During initial dentinogeneses 
Select and explain. 
A. Cell free zone is not visible, B. Cell rich zone is not visible, C. Both can be seen, D. Both can not be seen
A: Cell free zone is not visible
Answer: A: Cell free zone is not visible 
Explanation: None