This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
HLA III 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: HLAs corresponding to MHC class III encode components of the complement system. Ref: Ananthanarayanan & Panikers textbook of microbiology 9th edition pig: 140