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': 'The maximum permissible dose of radiation to the\noperator of an X-ray machine is \nSelect and explain. \nA. .05 rem per year, B. 0.5 rem per year, C. 5.0 rem per year, D. 50 rem per year', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]