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': 'Over filling may force materials directly in to the maxillary sinus most frequently in the case of: \nSelect and explain. \nA. Maxillary second premolar, B. Maxillary first premolar, C. Maxillary first molar, D. Facial root maxillary first premolar', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]