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': 'Retreatment Potaper system, False is \nSelect and explain. \nA. Has a non cutting tip, B. D1 with 0.30 mm diameter and 9% taper is used for coronal third, C. D2 with 0.25 diameter and 8% taper is used upto middle third, D. D3 with 0.20 diameter and 7% taper is used for apical third', 'role': 'user'}, {'content': 'Answer: A \nExplanation: It has a cutting tip unlike routine protaper system.', 'role': 'assistant'}]