This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction to Radiology, Subject name: Radiology
[{'content': 'S.I Unit of radioactivity is \nSelect and explain. \nA. Becquerel, B. Curie, C. Gray, D. Sieve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: UNITS OF RADIATION Physical quantity S.I. Unit Non S.I. Unit Conversion Radioactivity Becqueral (Bq) Curie (Ci) 1 Ci = 3.7 X 1010 Bq Absorbed dose Gray (Gy) Rad 1 Gy = 100 rads 1 rad = 0.01 gy Dose equivalent Sieve (SV) Rem 1 SV = 100 rem 1 Rem = 0.01 Sv Exposure coulomb/kg Roentgen 1R= 2.58 x 10-4coulomb/kg of air', 'role': 'assistant'}]