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': 'Sol- gel transformation is seen in \nSelect and explain. \nA. Impression plaster, B. Hydrocolloids, C. Elastomer, D. Impression compound', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The typical sol-gel reaction can be described simply as a reaction of soluble alginate with calcium ions from calcium sulfate and the formation of an insoluble calcium alginate.\nRef:\xa0 Phillips 12edition page no 172', 'role': 'assistant'}]