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 cyst is `deroofed' and the surrounding periosteum\nsutured to the margins of the cyst wall in \nSelect and explain. \nA. Decortication, B. Marsupialisation, C. Saucerization, D. Enucleation", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]