The diagram illustrates an electrolytic cell used to extract aluminium. Which statement is correct?
- AAluminium ions are oxidised in this process.
- BAluminium is liberated at the anode by the reaction $\text{Al}^{3+} + 3\text{e}^- \rightarrow \text{Al}$.
- CCryolite is purified aluminium oxide.
- DThe graphite anode burns away.