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: Biochemistry
[{'content': 'Reperfusion injury is caused by: \nSelect and explain. \nA. Vitamin E, B. Superoxide ion, C. Calcium ion, D. Magnesium ion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. Superoxide ion- Xanthine oxidase increases oxidative stress by generating superoxide free radiclesQ- Ischemic reperfusion injury is caused by reactive oxygen species (ROS)/free radical or pro oxidant like superoxide ionQAntioxidants blocking free radical formation include vitamin A (Beta carotene), C and E; superoxide dismutase, catalase and selenium containing glutathione peroxidase enzymes; ceruloplasmin, transferrin, ferritin, and lactoferrin transpo proteins etc.', 'role': 'assistant'}]