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 is gypsum die hardener 
Select and explain. 
A. Cyanoacrylate, B. Potassium sulphate, C. Calcium sulphate, D. Trisodium Phosphate
B: Potassium sulphate
Answer: B: Potassium sulphate 
Explanation: None