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
[{'content': 'The plasticizers used in polyether impression material is: \nSelect and explain. \nA. Polyether polymer, B. Colloidal silica, C. Glycol ether, D. Di-vinyl poly (dimethyl siloxane)', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]