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
The elastic or plastic deformation to fracture a material is its: 
Select and explain. 
A. Toughness, B. Brittleness, C. Young's Modulus, D. Proportional limit
A: Toughness
Answer: A: Toughness 
Explanation: None