The apparatus used to extract aluminium oxide by electrolysis is shown. Which equation shows a reaction occurring at the anode?
- A$\text{O} + 2\text{e}^- \rightarrow \text{O}^{2-}$
- B$2\text{O}^{2-} \rightarrow \text{O}_2 + 4\text{e}^-$
- C$\text{Al}^{3-} \rightarrow \text{Al} + 3\text{e}^-$
- D$\text{Al}^{3+} + 3\text{e}^- \rightarrow \text{Al}$