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': 'SI unit of radioactivity is: March 2013 (c, f) \nSelect and explain. \nA. Rem, B. Rad, C. Becuerel, D. Curie', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. C i.e. Becquerel', 'role': 'assistant'}]