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: Dental
Stiffness is? 
Select and explain. 
A. Resistance to elastic deformation, B. Degree of elastic deformation, C. Resistance to plastic deformation, D. Degree of plastic deformation
A: Resistance to elastic deformation
Answer: A: Resistance to elastic deformation 
Explanation: None