This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
The characteristic esophageal manometry finding in achalasia cardia is: 
Select and explain. 
A. Impaired lower esophageal sphincter relaxation and absent peristalsis, B. Impaired lower esophageal sphincter relaxation and increased peristalsis, C. Decreased lower esophageal sphincter pressure and absent peristalsis, D. Decreased lower esophageal sphincter pressure and increased peristalsis
A: Impaired lower esophageal sphincter relaxation and absent peristalsis
Answer: A: Impaired lower esophageal sphincter relaxation and absent peristalsis 
Explanation: Achalasia is characterized by impaired lower esophageal sphincter (LES) relaxation and absent peristalsis. Esophageal manometry is the most sensitive test to diagnose achalasia. Ref: Harrisons Principles of Internal Medicine, 18th Edition, Page 2431