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': 'Exclusively called cervical cementum is: \nSelect and explain. \nA. Acellular extrinsic fibre cementum., B. Acellular afibrillar cementum., C. Cellular intrinsic fiber cementum., D. Cellular mixed fiber cementum.', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Acellular afibrillar cementum is called cervical cementum, as they are found at cervical portion of the root only.', 'role': 'assistant'}]