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
[{'content': 'Which one of the following is a type of Electro-magnetic radiation? \nSelect and explain. \nA. Alpha rays, B. Beta rays, C. X-rays, D. Cathode rays', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]