This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
Chronic graft rejection occurs due to what type of hypersensitivity reaction 
Select and explain. 
A. Type IV, B. Type III, C. Type II, D. Type I
A: Type IV
Answer: A: Type IV 
Explanation: Graft rejection is an immunologic destruction of transplanted tissues or organs between two members or strains of a species differing at the major histocompatibility complex for that species (i.e., HLA in man and H-2 in the mouse). Ref microbiology textbook 8/e ananthnarayana