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': 'Catgut is commercially made from the intestine of the following animal: \nSelect and explain. \nA. Cat, B. Pig, C. Sheep, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Gut sutures derived from sheep submucosa or beef serosa are digested by proteolytic enzymes in the wound. They are more rapidly degraded in the presence of infection. The knot-holding ability of plain gut is rather inconsistent; chromic gut seems to be better in this regard. Plain gut--Plain gut incites an intense inflammatory reaction in the wound and loses its tensile strength within 2 weeks. Chromic gut--Treatment of gut with chromium salts decreases its tissue reactivity and prolongs its survival to about double that of plain gut. Ref: Jones T.R. (2011). Chapter 30. Wound Care. In R.L. Humphries, C. Stone (Eds), CURRENT Diagnosis & Treatment Emergency Medicine, 7e.', 'role': 'assistant'}]