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: Microbiology
Antibodies are most responsive to - 
Select and explain. 
A. Recipients tissue, B. Donor tissue, C. Isografts, D. Autograft
B: Donor tissue
Answer: B: Donor tissue 
Explanation: Ans. is 'b' i.e., Donor tissue During graft rejection antibodies are formed against donor tissue.