This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nuclear medicine, Subject name: Radiology
[{'content': 'Killing of Thyroid Cancer cells By I-131 is mainly by \nSelect and explain. \nA. Alpha Rays, B. X rays, C. Beta Rays, D. Gamma Rays', 'role': 'user'}, {'content': 'Answer: C \nExplanation: *I-131 produces both Gamma and Beta Rays, but killing of thyroid cancer is mainly done by Beta Rays.', 'role': 'assistant'}]