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': 'Portion of tooth brush that assists in removal of plaque is \nSelect and explain. \nA. Tip of brush, B. Tip of bristle, C. Sides of bristle, D. Whole brush', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]