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 function of 2% potassium sulphate in a gypsum product is: 
Select and explain. 
A. To regulate the setting expansion, B. Regulate setting time, C. Acts as retarder, D. None
B: Regulate setting time
Answer: B: Regulate setting time 
Explanation: None