In which of the following pairs of metals are both commercially extracted from their respective ores by the carbon reduction method?

The function of fluorspar in the electrolytic reduction of alumina dissolved in fused cryolite $(Na_3AlF_6)$ is

Among the following,an example of the thermite process is:

Identify the reaction that does not take place in a blast furnace.

Given are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Magnesium can reduce $Al_{2}O_{3}$ at a temperature below $1350^{\circ} C$,while above $1350^{\circ} C$ aluminium can reduce $MgO$.
Reason $R$: The melting and boiling points of magnesium are lower than those of aluminium.
In light of the above statements,choose the most appropriate answer from the options given below:

Cryolite $(Na_3AlF_6)$ helps in: