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
[{'content': 'Radiologic feature suggestive of Achalasia cardia is? \nSelect and explain. \nA. Absence of gastric air bubble, B. Air fluid level in mediastinum, C. Sigmoid ecophagus, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' ie., All of the above", 'role': 'assistant'}]