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
Middle age patient presents with dysphagia for liquids. The barium esophagogram of the patient is shown below. The diagnosis is: 
Select and explain. 
A. DES, B. Achalasia, C. NCE, D. Cancer
B: Achalasia
Answer: B: Achalasia 
Explanation: Ans. (b) AchalasiaRef: Sabistons Textbook of surgery, 20th Edition, Page 1015* Image shows bird-beak appearance of achalasia cardia