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
Pott puffy tumour occurs as complication of which sinusitis: 
Select and explain. 
A. Frontal, B. Sphenoid, C. Ethmoid, D. None of the above
A: Frontal
Answer: A: Frontal 
Explanation: 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.