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': '| energy linear acceleration used in \nSelect and explain. \nA. X-ray, B. Cathode rays, C. Photon rays, D. a- rays', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. X-ray', 'role': 'assistant'}]