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: Radiology
What is the average wavelength of the x-ray used in dentistry is: 
Select and explain. 
A. 0.6-1A°., B. 1-2A°., C. 0.5-2A°., D. 2-2.5A°.
A: 0.6-1A°.
Answer: A: 0.6-1A°. 
Explanation: Average wavelength of the x-ray used in dentistry is 0.6-1A°.