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': 'Sickle scaler in cross section appears \nSelect and explain. \nA. Round, B. Oval, C. Triangular, D. Half round', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]