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: Radiology
[{'content': 'Normal level of alveolar crest below the CEJ of the adjacent teeth is: \nSelect and explain. \nA. 0.5-1 mm, B. 1-1.5 mm, C. 1.5-2.0 mm, D. 1-2 mm', 'role': 'user'}, {'content': "Answer: B \nExplanation: ALVEOLAR CREST:\nThe gingival margin of the alveolar process that extends between the teeth is apparent on radiographs as a radiopaque line—the alveolar crest. The level of this bony crest is considered normal, when it is not more than 1.5 mm from the cementoenamel junction of the adjacent teeth.\nReference: White and Pharoah's Oral Radiology Principles and Interpretation 7th edition page no 133", 'role': 'assistant'}]