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 of medium Bristles tooth brush should be: \nSelect and explain. \nA. 0.1mm., B. 0.2mm., C. 0.3mm., D. 0.4mm.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Diameter of medium Bristles tooth brush is 0.3mm or 0.012 inch.', 'role': 'assistant'}]