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 sure sign of intestinal obstruction \nSelect and explain. \nA. Vomiting & distension, B. Jelly like stool, C. Diarrhoea, D. Localized tenderness', 'role': 'user'}, {'content': "Answer: A \nExplanation: Vomiting may or may not occur at the outset but becomes conspicuous and bile-stained with time. Initially, the passage of stool may be normal, whereas, later, blood and mucus are evacuated - the 'redcurrant jelly' stool.Classically, the abdomen is not initially distended; a lump that hardens on palpation may be discerned but this is present in only 60% of cases Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1194", 'role': 'assistant'}]