All of the Following Protein-Protein Interactions Are Involved in Activation

All of the following protein-protein interactions are involved in activation of naive helper T cells by antigen-presenting cells (APCs) EXCEPT binding of:

A) Peptide-MHC complexes on the APC to the TCR on the T cell
B) CD4 on the T cell to nonpolymorphic regions of class II MHC molecules on the APC
C) Integrins on the T cell with adhesion ligands on the APC
D) B7-2 on the APC with CD28 on the T cell
E) CD40L on the T cell with CD40 on the APC