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 setting time of zinc phosphate may be retarded by? 
Select and explain. 
A. Increase in the ratio of powder to liquid, B. Diluting the liquid with water, C. Increase the addition of powder to liquid, D. Decrease the addition of powder to liquid
D: Decrease the addition of powder to liquid
Answer: D: Decrease the addition of powder to liquid 
Explanation: None