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': 'Pott puffy tumour occurs as complication of which sinusitis: \nSelect and explain. \nA. Frontal, B. Sphenoid, C. Ethmoid, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: If infection in the frontal sinus spreads to the marrow of the frontal bone, localized osteomyelitis with bone destruction can result in a doughy swelling of the forehead classically described as Pott puffy tumour.', 'role': 'assistant'}]