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: Pathology
The role played by MHC proteins is to - 
Select and explain. 
A. Transduce the signal to T cells following antigen recognition, B. Mediate immunoglobulin class - switching, C. Present antigens for recognition by T cell antigen receptors, D. Enhance the secretion of cytokines
C: Present antigens for recognition by T cell antigen receptors
Answer: C: Present antigens for recognition by T cell antigen receptors 
Explanation: . Present antigens for recognition by T cell antigen receptors