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': 'Ideal angle the sharpening stone must form with the face of the blade is \nSelect and explain. \nA. 70 - 80 degrees, B. 90 - 100 degrees, C. 100 - 110 degrees, D. 120 - 130 degrees', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]