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 is a die hardener \nSelect and explain. \nA. Cyanoacrylate., B. Potassium sulphate., C. Sodium chloride., D. Resin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Die hardeners arc materials used to reinforce the surface of a die so as to make it more resistant of abrasion and scratching.\nDie hardeners used with gypsum dies:\n• Cyanoacrylate\n• Silver plating\n• Addition of die hardeners to gypsum', 'role': 'assistant'}]