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': 'Gates-Glidden drill is: \nSelect and explain. \nA. Flexible and used at low speed, B. Flexible and used at high speed, C. Inflexible and used at low speed, D. Inflexible and used at high speed', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]