This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Physiology
[{'content': "'Sigmoid' esophagus on Ba Swallow is seen in \nSelect and explain. \nA. Achalasia cardia, B. Scleroderma, C. Diffuse esophageal spasm, D. Carcinoma esophagus", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Esophageal motility disorders like diffuse esophageal spasm, presbyesophagus and nutcracker esophagus may show "cork screw" apperance.', 'role': 'assistant'}]