Answer
$A^+$ and $B^{2+}$ can oxidize $C^{2+}$.
Work Step by Step
Because in order to oxidize a species, other half reactions(which undergoes reduction) should have a more positive reduction potential than the oxidizing one. For instance, the reduction reaction of $C^{3+}$ has potential -0.12, first two reactions have more positive potentials i.e. 1.33 and 0.87 so they can oxidize $C^{2+}$ to $C^{3+}$.
