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 etching pattern is optimal for bonding? \nSelect and explain. \nA. Type 1, B. Type II, C. Type III, D. Type IV', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Three types of etched patterns are noted. They are:\n\n\xa0Type I: Etched enamel surface in which the center of enamel rods is dissolved with periphery intact\n\xa0Type II: There is peripheral dissolution of enamel rods\n\xa0Type III: It is a combination of the above two patterns\n\nFor optimum bond strength, Type I pattern is preferred.', 'role': 'assistant'}]