This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oesophagus, Subject name: Surgery
Most common motility disorder leading to dysphagia: 
Select and explain. 
A. Nut cracker esophagus, B. Esophageal web, C. Diffuse esophageal spasm, D. Achalasia cardia
D: Achalasia cardia
Answer: D: Achalasia cardia 
Explanation: Ans. (d) Achalasia cardiaRef: Sabiston 20th Edition, Pagesl015-1018* Most common motility disorder -- Achalasia* Most common hypermotility disorder: Nut cracker esophagus