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': 'According to ADA specification #1 for amalgam, what is the acceptable dimensional change? \nSelect and explain. \nA. -20 to +20 micron/cm, B. -10 to +10 micron/cm, C. -20 to +10 micron/cm, D. -10 to +20 micron/cm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: According to ADA specification #1 for amalgam, the acceptable dimensional change is -20 to +20 micron/cm.\nReference: Marzouk Operative dentistry, pg-108', 'role': 'assistant'}]