In the context of the Hall - Heroult process for the extraction of Al, which of the following statements is false?

CO and $\displaystyle \mathrm{CO}_2$ are produced in this process

$\displaystyle \mathrm{Al}_2 \mathrm{O}_3$ is mixed with $\displaystyle \mathrm{CaF}_2$ which lowers the melting point of the mixture and brings conductivity

$\displaystyle \mathrm{Al}^{3+}$ is reduced at the cathode to form Al

$\displaystyle \mathrm{Na}_3 \mathrm{AlF}_6$ serves as the electrolyte