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: Pathology
[{'content': 'Hyperacute rejection is due to - \nSelect and explain. \nA. Preformed antibodies, B. Cytotoxic T-lymphocyte medicated injury, C. Circulating macrophage mediated injury, D. Endothelitis caused by donor antibodies', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Preformed antibodies", 'role': 'assistant'}]