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
Dimension stability of hydrocollids may be achieved by 
Select and explain. 
A. optimizing w:p, B. using cold water, C. prolonged manipulation, D. using humidor
D: using humidor
Answer: D: using humidor 
Explanation: None