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': 'Indication of gingivectomy is \nSelect and explain. \nA. edema of gingiva, B. infrabony pockets, C. adequate attached gingiva, D. pocket depth below mucogingival junction', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]