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
SI unit of dose of radiation absorption – 
Select and explain. 
A. Rad, B. REM, C. Gray, D. Curie
C: Gray
Answer: C: Gray 
Explanation: The old unit of radiation absorption is rad and new (SI) unit is gray.