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': 'Which of the following hardness test is not used for brittle material: \nSelect and explain. \nA. Rockwell test., B. Brinell test., C. Both., D. None.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: HARDNESS TEST\n\nKnoop hardness test\nVicker’s/diamond pyramid test\n\nNot for BRITTLE material \n\nRockwell\nBrinells', 'role': 'assistant'}]