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
Which one of the following is a type of Electro-magnetic radiation? 
Select and explain. 
A. Alpha rays, B. Beta rays, C. X-rays, D. Cathode rays
C: X-rays
Answer: C: X-rays 
Explanation: None