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 cement which is least soluble in oral cavity: \nSelect and explain. \nA. Glass ionomer, B. Resin cement, C. Polycarboxylate cement, D. Silica — phosphate cement', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]