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': 'True about cathode-anode circuit is: \nSelect and explain. \nA. Step up transformer, B. Step down transformer, C. 1 and 2, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cathode – anode circuit has a step-up transformer (SUP) because the voltage has to be stepped up from 220 V to 65,000 V.', 'role': 'assistant'}]