This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transplantation, Subject name: Surgery
Hyper acute rejection is due to: 
Select and explain. 
A. Preformed antibodies, B. Cytotoxic T-lymphocyte medicated injury, C. Circulating macrophage mediate injury, D. Endothelitis caused by donor antibodies
A: Preformed antibodies
Answer: A: Preformed antibodies 
Explanation: Ans. (a) Preformed antibodiesRef: Bailey 26th edition, Page 1412* Hyperacute happens in minutes to hours due to preformed antibodies.