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': 'Advantage of NiTi over K-files? \nSelect and explain. \nA. Increased flexibility, B. Low resiliency, C. Resistance to breakage, D. Less expensive', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]