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': 'Passive impression technique involves: \nSelect and explain. \nA. Impression with silicone, B. Impression compound, C. Impression plaster, D. Alginate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]