This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, Subject name: ENT
Xray showing air column between soft tissue mass and posterior wall of nasopharynx is suggestive of - 
Select and explain. 
A. Ethmoidal polyp, B. Antrochoanal polyp, C. Nasalmyiasis, D. None of the above
B: Antrochoanal polyp
Answer: B: Antrochoanal polyp 
Explanation: Ans. is 'b' i.e., Antrochoanal polyp o On xray.antrochoanal polyp appears as a soft tissue density and shows a column of air between the soft tissue mass and posterior wall of nasopharynx.