This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Liver, Subject name: Surgery
[{'content': 'On barium swallow the grade IV esophageal varices appear as: \nSelect and explain. \nA. Mucosal folds above the carina, B. Mucosal folds below the carina, C. Mucosal folds at the carina, D. A thick band', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Mucosal fold below carinaBarium features of Esophageal Varices:* Serpiginous (Worm like) filling defects in esophagus* Varices seen in Barium Swallow below the carina levelThe best investigation to diagnose Esophageal Varices- UGI Endoscopy', 'role': 'assistant'}]