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
Which of the following impression materials is easy to pour and difficult to remove the stone cast from the impressions? 
Select and explain. 
A. Addition polysilicone, B. Condensation polysilicone, C. Polyether, D. Polysulfide
C: Polyether
Answer: C: Polyether 
Explanation: None