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': 'In self threaded pins, the pin hole is smaller than pin channel by diameter: \nSelect and explain. \nA. 0.001 inch, B. 0.002 inch, C. 0.003 inch, D. 0.004 inch', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]