This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Abdominal Radiography, Subject name: Radiology
[{'content': 'The Barium Swallow shows? \nSelect and explain. \nA. Achalasia cardia, B. GERD, C. Nut cracker esophagus, D. Malignancy', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) Nut cracker esophagus.', 'role': 'assistant'}]