This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
Curie is the unit for - 
Select and explain. 
A. Radiation emitted, B. Radiation absorbed, C. Radioactivity, D. All of the above
C: Radioactivity
Answer: C: Radioactivity 
Explanation: Park's textbook of preventive and social medicine 23rd edition. * The activity of a radioactive material is the number of nuclear disintegration per unit time.the unit of activity was Curie earlier and Becquerel now.