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': 'Best range of UV light used for treatment of skin diseases \nSelect and explain. \nA. 100 – 200 nm, B. 200 – 400 nm, C. 400 – 700 nm, D. > 700 nm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: UV light most commonly used in dermatology are UVB (290 - 320 mn), narrow band UVB (311 nm), and UVAi (360 - 380 nm).', 'role': 'assistant'}]