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
'Sigmoid' esophagus on Ba Swallow is seen in 
Select and explain. 
A. Achalasia cardia, B. Scleroderma, C. Diffuse esophageal spasm, D. Carcinoma esophagus
A: Achalasia cardia
Answer: A: Achalasia cardia 
Explanation: Esophageal motility disorders like diffuse esophageal spasm, presbyesophagus and nutcracker esophagus may show "cork screw" apperance.