This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'One of the following opens into middle meatus of nose \nSelect and explain. \nA. Naso-lacrimal duct, B. Eustachian tube, C. Sphenoidal sinus, D. Maxillary sinus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The middle meatus presents the ethmoidal bulla,the hiatus semilunaris,the infundibulum and the opening of frontal,maxillary and the middle ethmoidal air sinuses.Sphenoidal air sinus opens into the sphenoethmoidal recess,which is a triangular fossa just above the superior concha. REF.BDC VOL.3,5th edition.', 'role': 'assistant'}]