Final answer:
MHC molecules bind diverse peptide antigens because they are promiscuous.
Step-by-step explanation:
The reason why MHC molecules can bind diverse peptide antigens is e. MHC molecules are promiscuous.
MHC molecules have the ability to bind a wide variety of peptides, making them versatile in antigen presentation and immune response.
This promiscuity allows MHC molecules to recognize and present a diverse range of antigens to the immune system.