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': 'Intra enamel depth preparation in porcelain laminate\nveneer \nSelect and explain. \nA. 0.5 mm, B. 0.75 mm, C. 1 mm, D. 2 mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]