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
Which material undergoes hysteresis? 
Select and explain. 
A. Irreversible hydrocolloid, B. Reversible hydrocolloid, C. Impression plaster, D. Metallic oxide paste
B: Reversible hydrocolloid
Answer: B: Reversible hydrocolloid 
Explanation: None