In the electrolytic extraction of aluminium,cryolite is used:

Blisters on copper are produced due to the evolution of which gas?

Which metals are extracted using the self-reduction method?

In which metallurgical process is the metal obtained in the molten state?

Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of

Given below are two statements.
Statement $I$: According to the Ellingham diagram,any metal oxide with higher $\Delta G^{\circ}$ is more stable than the one with lower $\Delta G^{\circ}$.
Statement $II$: The metal involved in the formation of oxide placed lower in the Ellingham diagram can reduce the oxide of a metal placed higher in the diagram.
In the light of the above statements,choose the correct answer from the options given below.