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': 'Genioplasty procedure is used \nSelect and explain. \nA. To change the attachment of genioglossus muscle in pre-prosthetic procedure, B. To change the position of genial tubercles, C. To modify the position of the chin, D. To modify the attachment of anterior belly of digastric', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]