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 nonaqueous elastomeric impression materials has the least shelf life 
Select and explain. 
A. Poly ether, B. Addition silicone, C. Condensation silicone, D. Polysulphide
A: Poly ether
Answer: A: Poly ether 
Explanation: None