This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiotherapy Pa 1, Subject name: Radiology
[{'content': 'Which of the following is used in External Beam Radiotherapy? \nSelect and explain. \nA. I-131, B. P-32, C. I-125, D. LINAC', 'role': 'user'}, {'content': 'Answer: D \nExplanation: External Beam Radiotherapy(EB/TELETHERAPY) is done using C0-60/Cs-137 which produce Gamma Rays Nowadays EB/TELETHERAPY is usually done using Linear Accelerator/LINAC which uses Xrays', 'role': 'assistant'}]