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': 'In amalgam cavity preparation the cavosurface beveled at: \nSelect and explain. \nA. Less than 90°, B. Less than 45°, C. More than 10°, D. At an obtuse angle', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]