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: Anatomy
Maxillary sinus drains into ? 
Select and explain. 
A. Inferior meatus, B. Middle meatus, C. Superior meatus, D. Sphenoethmoidal recess
B: Middle meatus
Answer: B: Middle meatus 
Explanation: Middle meatus