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': 'Diameter at D16 of file 35 \nSelect and explain. \nA. 0.67mm, B. 0.35mm, C. 0.067mm, D. 0.035mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]