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: Surgery
Radiologic feature suggestive of Achalasia cardia is? 
Select and explain. 
A. Absence of gastric air bubble, B. Air fluid level in mediastinum, C. Sigmoid ecophagus, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Ans. is 'd' ie., All of the above