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': 'Definitive diagnosis of sinusitis is by- \nSelect and explain. \nA. Transillumination, B. Endoscopy, C. X - ray, D. Proof puncture', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]