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': 'Ideal pulpal depth for amalgam restoration in a primary molar is \nSelect and explain. \nA. 0.5 mm from DEJ, B. 1 mm from enamel surface, C. 1.5 mm from DEJ, D. 3.2 mm from enamel surface', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]