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': 'A 32 year old female patient underwent extraction of an upper first molar on right side and 0.3 mm of perforation was created into the sinus wall.\nOroantral communication is predominantly seen during extraction of \nSelect and explain. \nA. Maxillary premolars, B. Maxillary first molars, C. Maxillary second molar, D. Maxillary paramolar', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]