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 crown of any tooth can be subdivided for description, into \nSelect and explain. \nA. Halves, B. Thirds, C. Quarters, D. Eights', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]