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: Surgery
[{'content': 'Y.V plasty procedure is used for \nSelect and explain. \nA. Vestibuloplasty, B. Ridge augmentation, C. Frenectomy, D. Mucogingival surgery', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]