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: The osteomeatal complex is a narrow anatomical region consisting of:-\n\n\nMultiple bony structures (middle turbinate, uncinate process, Bulla ethmoidalis).\nAir spaces (frontal recess, ethmoidal infundibulum, middle meatus)\nOstia of anterior ethmoidal, maxillary and frontal sinuses →\xa0, therefore, connects these sinuses to nasal cavity.', 'role': 'assistant'}]