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': 'Antral sign is seen in - \nSelect and explain. \nA. Juvenile angiofibroma, B. Otosclerosis, C. CSOM, D. Sinusitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Antral sign or Holman-Miller sign (anterior bowing of posterior wall of maxillary sinus) on CT scan is pathognomic of JNA.', 'role': 'assistant'}]