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 adhesion, C. Trauma, D. Carcinoma', 'role': 'user'}, {'content': "Answer: B \nExplanation: Adhesion secondary to previous surgery are by far the most common cause for small bowel obstruction. Adhesions paicularly after pelvic surgery are responsible for more than 60% of cause of small bowel obstruction. Causes of small bowel obstruction in order of frequency: Adhesions (Approximately 60%) commonest Malignant tumors (approximately 20%) second most common cause. Most commonly these tumors are metastatic lesions. Hernias (Approximately 10%) Crohn's disease (approximately 5%) Ref: Sabiston 18/e, Page 1290.", 'role': 'assistant'}]