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 No or number 1, the minimum compressive strength for silver amalgam filling after one hour should be \nSelect and explain. \nA. 80 Mpa, B. 140 Mpa, C. 260 Mpa, D. 510 Mpa', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]