A.(−)Fe(s)│Fe2+(c1), Fe3+(c2)║Cr2O72-(c3), Cr3+(c4), H+(c5)│Pt(s)(+)
B.(−)Fe2+(c1), Fe3+(c2)║Cr2O72-(c3), Cr3+(c4), H+(c5)│Pt(s)(+)
C.(−)Pt(s)│Cr2O72-(c3), Cr3+(c4),H+(c5)║Fe3+(c2),Fe2+(c1)│Pt(s)(+)
D.(−)Pt(s)│Fe2+(c1), Fe3+(c2)║Cr2O72-(c3), Cr3+(c4),H+(c5)│Pt(s)(+)