Once Expressed on the Surface of Host Cells, an MHC

Once expressed on the surface of host cells, an MHC protein remains stably associated with its bound peptide for several days. This highly stable peptide binding behavior is important because:

A) It prevents peptide exchanges on the cell surface, ensuring that peptide:MHC complexes are reliable indicators of the proteins present inside that host cell.
B) If the MHC protein lost its peptide it would become unstable, and would be rapidly internalized and degraded.
C) Pathogens would otherwise evade the immune response by making decoy peptides that mimic host cell peptides.
D) Pathogens would be able to evade the T cell response by making proteases that cleave MHC proteins inducing peptide release.
E) Immune responses to infection often induce noxious chemicals that damage surface MHC proteins, and might result in peptide loss.