This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
MCH class 3 genes encodes 
Select and explain. 
A. Complement components C3, B. Tumor necrosis factor, C. IL2, D. Beta 2microglobulin
B: Tumor necrosis factor
Answer: B: Tumor necrosis factor 
Explanation: Ref Robbins 9/e p194-195 Anantha Narayana 6/e p121; Harrison 17/e p2047 Class III molecules include several secreted proteins with immune functions: components of the complement system (such as C2, C4, and B factor), cytokines (such as TNF-a, LTA, and LTB), and heat shock proteins.