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: Radiology
[{'content': "Investigation of choice for Zenker's diverticulum is – \nSelect and explain. \nA. Barium swallow, B. Endo s c opy, C. Esophageal manometry, D. CT", 'role': 'user'}, {'content': "Answer: A \nExplanation: Barium swallow is the initial ivestigation of choice for Zenker's diverticulum (pharyngeal pouch).", 'role': 'assistant'}]