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
Greatest stress generated in a material till it follows a directly proportional relationship 
Select and explain. 
A. Yield Strength, B. Proportional Limit, C. Toughness, D. Ultimate strength
B: Proportional Limit
Answer: B: Proportional Limit 
Explanation: None