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': 'In acute sinusitis, the sinus most often involved in children is: \nSelect and explain. \nA. Maxillary, B. Sphenoid, C. Ethmoid, D. Frontal', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Most common sinusitis in children is Ethmoid. Most common sinusitis in adults is Maxillary.', 'role': 'assistant'}]