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': 'Intermediate cementum is found at: \nSelect and explain. \nA. Coronal portion of the root., B. Apical third of the root., C. Middle third of the root., D. Covers whole the root', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Intermediate cementum mostly found at apical third of posterior teeth.', 'role': 'assistant'}]