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
Definitive diagnosis of sinusitis is by- 
Select and explain. 
A. Transillumination, B. Endoscopy, C. X - ray, D. Proof puncture
B: Endoscopy
Answer: B: Endoscopy 
Explanation: None