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': 'Tooth Brush has bristles arranged in \nSelect and explain. \nA. 2 -3 rows, B. 2-4 rows, C. 3-4 rows, D. 1-2 rows', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]