This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oesophagus, Subject name: Surgery
[{'content': 'Best view for Tracheo-esophageal groove is: \nSelect and explain. \nA. Left atrial, B. Right atrial, C. Left ventricular, D. Right ventricular', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (Left atrial) (994-Bailey & Love 24th)Tracheo-oesophageal fistulaA lateral chest radiograph shows a lucent proximal pouch that may displace the trachea anteriorly. If bowel gas is present there must be a fistula to the distal oesophagus.* In case of doubt Air (preferred) or a small amount of contrast medium can be injected through the nasogastric tube. Gas in the stomach confirms that there is fistula between the trachea and distal oesophagus.', 'role': 'assistant'}]