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
In acute sinusitis, the sinus most often involved in children is: 
Select and explain. 
A. Maxillary, B. Sphenoid, C. Ethmoid, D. Frontal
C: Ethmoid
Answer: C: Ethmoid 
Explanation: Most common sinusitis in children is Ethmoid. Most common sinusitis in adults is Maxillary.