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': "Life-saver shaped enlargements of the marginal gingival\nare called \nSelect and explain. \nA. Gingival crater, B. McCall festoons, C. Stillman's cleft, D. Window peaks", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]