This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Malabsorbtion Syndrome, Subject name: Medicine
[{'content': 'Which investigation is not required in diagnosis of Achalasia? \nSelect and explain. \nA. Esophageal manometry, B. Barium swallow, C. Anti-neuronal antibodies, D. Enterocylsis', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Investigation Diagnosis CTchest Pseudoachalasia Endoscopic Ultrasound Pseudoachalasia Anti-neuronal antibodies Para neoplastic manifestation Enterocylsis Study small bowel using contrast study', 'role': 'assistant'}]