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
[{'content': 'POEM is used for: \nSelect and explain. \nA. Achalasia cardia, B. Cancer esophagus, C. Diffuse esophageal spasm, D. Nutcracker esophagus', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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', 'role': 'assistant'}]