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
HLA HI gene codes for - 
Select and explain. 
A. Immunological reaction in graft rejection, B. Complement, C. Graft versus host reaction, D. Immunoglobulins
B: Complement
Answer: B: Complement 
Explanation: Ans. is 'b' i.e., Complement