The direct pathway of allorecognition involves interaction of _____, whereas the indirect pathway of ...

The direct pathway of allorecognition involves interaction of _____, whereas the indirect pathway of alloreaction involves interaction of _____.
 
  a. donor T cells with allogeneic HLA molecule on recipient dendritic cells; recipient T cells with allogeneic HLA molecules on donor dendritic cells
  b. recipient T cells with allogeneic HLA molecules on donor dendritic cells; donor T cells with allogeneic HLA molecule on recipient dendritic cells
  c. recipient T cells with allogeneic HLA molecules on donor dendritic cells; recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells
  d. recipient T cells with peptides of allogeneic HLA molecules on recipient dendritic cells; donor T cells with peptides of allogeneic HLA molecules on donor dendritic cells.