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': 'Radiological feature of ischemic colitis is \nSelect and explain. \nA. Saw toothing, B. Craggy popcorn appearance, C. Thumb printing, D. Cobble stone appearance', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Thumb printing', 'role': 'assistant'}]