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
Material of choice for single-step border moulding is 
Select and explain. 
A. Polyether, B. Greenstick compound., C. ZOE, D. None
A: Polyether
Answer: A: Polyether 
Explanation: Single step or simultaneous border moulding:
It is a process, in which the entire periphery of the tray is refined in a single step. Polyether impression material is the material of choice because it fulfills all the requisites.