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
[{'content': 'During initial dentinogeneses \nSelect and explain. \nA. Cell free zone is not visible, B. Cell rich zone is not visible, C. Both can be seen, D. Both can not be seen', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]