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': 'A 12 years child presents with B/L nasal pink masses. Most important investigation prior to undertaking surgery is - \nSelect and explain. \nA. Ultrasound, B. FNAC, C. Biopsy, D. Contrast C.T. Scan', 'role': 'user'}, {'content': 'Answer: D \nExplanation: CT scan of head with contrast enhancement is the investigation of choice for JNA.', 'role': 'assistant'}]