This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Esophagus, Subject name: Surgery
POEM is used for: 
Select and explain. 
A. Achalasia cardia, B. Cancer esophagus, C. Diffuse esophageal spasm, D. Nutcracker esophagus
A: Achalasia cardia
Answer: A: Achalasia cardia 
Explanation: Per Oral Endoscopic Myotomy (POEM) POEM is the application of esophageal myotomy to the concept of NOTES*by submucosal tunneling method . Used for treatment of achalasia Involves creation of long esophageal myotomy using flexible endoscope *NOTES - Natural Orifice Transluminal Endoscopic Surgery