In Cells with Mutations in Either TAP1 or TAP2

In cells with mutations in either TAP1 or TAP2:

A) ubiquitin conjugation would be disrupted and antigen proteins would not be tagged for destruction.
B) ubiquitin-conjugated proteins would not be destroyed by proteasomal proteolysis.
C) peptides generated by proteasomal proteolysis would not be complexed with class I MHC molecules.
D) class I MHC-antigen complexes would be unable to cross the ER membrane.