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: None', 'role': 'assistant'}]