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 is stiffest of all elastomeric impression material: 
Select and explain. 
A. Polysulphides., B. Condensation silicone., C. Addition silicone., D. Polyether
D: Polyether
Answer: D: Polyether 
Explanation: None