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': 'Seibert’s class II defect is: \nSelect and explain. \nA. Faciolingual loss of tissues with normal ridge height, B. Normal ridge width with loss of ridge height, C. Loss of height and width, D. None of the above', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Seibert’s\xa0Classification\nClass 0 defects - No defect.\nClass I defects - Faciolingual loss of tissue width with normal ridge height.\nClass II defects - Loss of ridge height with normal ridge width.\nClass III defects - A\xa0combination of loss in both dimensions.', 'role': 'assistant'}]