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
What is the polymerization shrinkage if 3:1 powder: liquid ratio is used? 
Select and explain. 
A. 6%, B. 8%, C. 10%, D. 21%
A: 6%
Answer: A: 6% 
Explanation: None