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': 'Calculate D3 for file with 2% taper, and D0 = 0.1 mm \nSelect and explain. \nA. 0.16 mm, B. 0.18 mm, C. 0.20 mm, D. 0.30 mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]