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
Trasplantation 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: Ans. is 'b' i.e., Kidney