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': 'Sinusitis in children is commoner in which sinus: \nSelect and explain. \nA. Frontal, B. Maxillary, C. Ethmoid, D. Sphenoid', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The commonest sinus involved was ethmoidal in children and mixed sinus pathology in adults. The majority of patients responded to medical treatment. CONCLUSION: Orbital complications of sinusitis are commoner in children than adults and have orable prognosis.', 'role': 'assistant'}]