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': 'Gillmore needle is used for \nSelect and explain. \nA. Testing the strength of plaster of paris, B. Evaluating the setting time of plaster of paris, C. Testing the metal hardness, D. Testing the purity of noble metals', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]