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': 'Spastic ileus is seen in: \nSelect and explain. \nA. Porphyria, B. Retroperitoneal abscess, C. Hypokalemia, D. MI', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Spastic Ileus Spastic ileus or dynamic ileus is rare, results from extreme and prolonged contraction of the intestine Spastic ileus is seen in: Heavy metal poisoning Uremia Porphyria Extensive intestinal ulceration Ref: Harrison 19th edition Pgno: 1982', 'role': 'assistant'}]