This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'The most common cause of small intestinal obstruction is \nSelect and explain. \nA. Intussusception, B. Iatrogenic adhesions, C. Trauma, D. Carcinoma', 'role': 'user'}, {'content': "Answer: B \nExplanation: Causes of small bowel obstruction in order of frequency \xa0: (Sabiston)\nI. Adhesions (~60%) Commonest\n\nMalignant tumors (20%) Second most common cause. Most commonly, these tumors are metastatic lesions\nHernias (~10%)\nCrohn's disease (~5%)", 'role': 'assistant'}]