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': 'The knoop Hardness Number of Microfilled Composite Restorative material ranges from: \nSelect and explain. \nA. 50 — 60 KHN, B. 25 — 35 KHN, C. 15 — 20 KHN, D. 40 — 48 KHN', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]