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': "Paranasal sinuses are affected by both benign and malignant neoplasms. Commonest benign tumour of paranasal sinuses are: \nSelect and explain. \nA. Angiofibroma, B. Adenocarcinoma, C. Osteomas, D. Burkitt's lymphoma", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Osteomas are the most common tumors of the paranasal sinuses. They are most commonly seen in the frontal sinus followed in turn by those of ethmoid and maxillary. They may remain asymptomatic. Treatment is indicated when they become symptomatic.', 'role': 'assistant'}]