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
What is the wavelength of light used in light cure system: 
Select and explain. 
A. 400nm, B. 474nm., C. 500nm, D. Any of the above.
B: 474nm.
Answer: B: 474nm. 
Explanation: The range is 400-500nm.
But if question has been asked for specific wavelength then 474nm is more appropriate.