This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'Investigation of choice for oesophagal rupture is \nSelect and explain. \nA. CT chest, B. Rigid esophagoscopy, C. Barium contrast swallow, D. Plain Xray', 'role': 'user'}, {'content': "Answer: A \nExplanation: CT Chest more accurate, Chest X-ray shows pneumomediastinum. Reference: SRB's Manual of Surgery, 6th Edition, page no= 802, 793.", 'role': 'assistant'}]