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': 'With slowly advancing enamel caries and rapid involvement of dentin type of dentin formed is \nSelect and explain. \nA. Secondary, B. Tertiary, C. Reparative, D. Sclerotic', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]