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': 'An old man who is edentulous developed squamous cell Ca in buccal mucosa that has infiltrated to the alveolus. Following is not indicated in treatment : \nSelect and explain. \nA. Radiotherapy, B. Segmental mandibulectomy, C. Marginal mandibulectomy involving removal of the outer table only, D. Marginal mandibulectomy involving removal of upper half of mandible', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]