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': 'Corononal 3rd root fracture occurs: \nSelect and explain. \nA. Above bone crest., B. Below bone crest., C. Any of the above., D. None of the above.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Middle 3rd root fracture occurs below bone crest.', 'role': 'assistant'}]