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: Radiology
[{'content': 'String sign is seen in – \nSelect and explain. \nA. Crohns disease, B. TB of the ileocaecal region, C. Idiopathic hyperophic pyloric stenosis, D. All of the above', 'role': 'user'}, {'content': "Answer: D \nExplanation: String sign → Congenital hypertrophic pyloric stenosis, Ileocecal tuberculosis.\nString sign of Kantor → Crohn's disease\nString of bead sign → Small bowel obstruction", 'role': 'assistant'}]