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': 'The middle to apical third of the root surface and furcations are covered by \nSelect and explain. \nA. Acellular extrinsic fiber cementum, B. Acellular intrinsic fiber cementum, C. Cellular intrinsic fiber cementum, D. Cellular extrinsic fiber cementum', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]