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
Oesophageal manometry is used in: 
Select and explain. 
A. Cancer esophagus, B. Barrett esophagus, C. Schatzki ring, D. Achalasia cardia
D: Achalasia cardia
Answer: D: Achalasia cardia 
Explanation: Ans. (d) Achalasia CardiaRef Bailey and Love 26th edition Page 1015* Manometry is the investigation to study the physiology of the functions of esophagus.* It is the investigation of choice to detect the motility disorders like achalasia cardia, DES, nut cracker esophagus.* Barrett IOC: Endoscopic biopsy* Cancer Esophagus IOC: Endoscopic biopsy* Zenker IOC: Barium swallow