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
Addition of 4% potassium sulfate and 0.4% borax to impression plaster helps in 
Select and explain. 
A. Regulating setting time and expansion, B. Imparting colour and taste, C. Regulating strength and consistency, D. Adhering to tray during impression
A: Regulating setting time and expansion
Answer: A: Regulating setting time and expansion 
Explanation: None