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': 'The most common serious complication which can occur following surgery in maxillary incisor region is \nSelect and explain. \nA. Iritis, B. Cellulitis, C. Periapical abscess, D. Cavernous sinus thrombisis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]