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': 'Early stage of carcinoma esophagus is diagnosed by \nSelect and explain. \nA. Barium meal, B. Trans oesophageal USG, C. MRI, D. Fluoroscopy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .investigations for carcinoma oesophagus includes 1)barium swallow -shouldering sign and irregular filling defect.RAT TAIL defect in fluoroscopy is typical. 2)oesophagoscopy -to know lesion, extent and types. 3)biopsy -histological evaluation 4)X-ray /CT/MRI/ bronchoscopy/chromoendoscopy/oesophageal endosonography ref: SRB&;s manual of surgery,5th ed, pg no 806', 'role': 'assistant'}]