This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
Transplantation of which one of "the following organs is most often associated with hyper-acute rejection? 
Select and explain. 
A. Hea, B. Kidney, C. Lungs, D. Liver
B: Kidney
Answer: B: Kidney 
Explanation: Hyperacute rejection is due to the presence in the recipient of preformed antibodies against HLA class I antigens expressed by the donor. Antibody mediated rejection generally occurs hours to days after transplantation. Kidney transplants are paicularly vulnerable to hyperacute graft rejection, whereas hea and liver transplants are relatively resistant. Bailey and love 27th edition Pg: 1535