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': 'What is the diagnosis \nSelect and explain. \nA. Pneumpthorax, B. Duodenal perforation, C. Hiatus hernia, D. Pleural effusion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Plain chest radiograph of a perforated ulcer, showing air under the diaphragm.An erect plain chest radiograph will reveal free gas under the diaphragm in excess of 50% of cases with perforated peptic ulcer but CT imaging is more accurate. All patients should have serum amylase performed, as distinguishing between peptic ulcer, perforation and pancreatitis can be difficult.Bailey and love 27e 1125', 'role': 'assistant'}]