Group-$13$ elements react with ${\mathrm{O}}_2$ in amorphous form to form oxides of type ${\mathrm{M}}_2{\mathrm{O}}_3$ ($\mathrm{M}=$ element). Which among the following is the most basic oxide?

Given below are two statements: one is labelled as Assertion $\mathrm{A}$ and the other is labelled as Reason $\mathrm{R}$

Assertion $\mathrm{A}$: Boron is unable to form ${\mathrm{BF}}_6^{3-}$

Reason $\mathrm{R}$: Size of $\mathrm{B}$ is very small.

In the light of the above statements, choose the correct answer from the options given below

Given below are two statements:

Statement I: During Electrolytic refining, the pure metal is made to act as anode and its impure metallic form is used as cathode.
Statement II: During the Hall-Heroult electrolysis process, purified ${\mathrm{Al}}_2{\mathrm{O}}_3$ is mixed with ${\mathrm{Na}}_3{\mathrm{AlF}}_6$ to lower the melting point of the mixture.
In the light of the above statements, choose the most appropriate answer from the options given below:

Given below are two statements: one is labelled as Assertion $\mathrm{A}$ and the other is labelled as Reason $\mathrm{R}$.

Assertion $\mathrm{A}:$ In $\mathrm{T}l{\mathrm{I}}_3,$ isomorphous to ${\mathrm{CsI}}_3$, the metal is present in $+1$ oxidation state.

Reason $\mathrm{R}:$ $\mathrm{T}l$ metal has fourteen $\mathrm{f}$ electrons in its electronic configuration.

In the light of the above statements, choose the most appropriate answer from the options given below: