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: ENT
[{'content': 'Osteomeatal complex (OMC) connects: \nSelect and explain. \nA. Nasal cavity with maxillary sinus, B. Nasal cavity with sphenoid sinus, C. The two nasal cavities, D. Ethmoidal sinus with ethmoidal bulla', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Osteomeatal complex lies in the middle meatus.It is the final common drainage pathway for the maxillary, frontal and anterior ethmoid sinuses into the nasal cavity.', 'role': 'assistant'}]