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': 'Process of canal preparation shown in color plate is called as: \nSelect and explain. \nA. Crown down technique, B. Step back technique, C. Balanced force technique, D. Standardized technique', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]