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: Surgery
[{'content': 'Second swallowing in barium meal studies is found in- \nSelect and explain. \nA. Pharyngeal pouch, B. Achalasia cardia, C. Scleroderma, D. Reflux esophagitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: • Second swallow is due to regurgitation of barium from pharyngeal pouch', 'role': 'assistant'}]