The diagram illustrates a method used to copper-plate a pan. Which equation shows the reaction at the cathode?
- A$\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}$
- B$2\text{H}^+ + 2e^- \rightarrow \text{H}_2$
- C$4\text{OH}^- \rightarrow \text{O}_2 + 2\text{H}_2\text{O} + 4e^-$
- D$2\text{O}^{2-} \rightarrow \text{O}_2 + 4e^-$