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': 'Technique that is best suited for preparing fine and curved canals \nSelect and explain. \nA. step back, B. step down, C. crown down, D. Modified double flare technique', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]