Answer
C
Work Step by Step
1) No change in NOX of any species.
2) Cu and Cl change their NOXs: $Cu:0, Cl_2:0, Cu^{2+}:+2,Cl^-:-1$
3) No change in NOX of any species.
4) S and I change their NOXs: $I^-2:0,S_2O_3^{2-}, (S):+2,\ I^-:-1,\ S_4O_6^{2-}, (S):+2.5$