$2-$Methyl propyl bromide reacts with ${\mathrm{C}}_2{\mathrm{H}}_5{\mathrm{O}}^{-}$and gives $‘\mathrm{A}’$ whereas on reaction with ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}$ it gives $‘\mathrm{B}’.$ The mechanism followed in these reactions and the products $‘\mathrm{A}’$ and $‘\mathrm{B}’$ respectively are:

In the reaction

The major product of the following reaction is:

The increasing order of reactivity of the following compounds towards reaction with alkyl halides directly is:

$\left(i\right)$

$\left(ii\right)$

$\left(iii\right)$

$\left(iv\right)$

For the following compounds the correct statement(s) with respect to nucleophilic substitution reactions is(are)

The reagent required for the following two step transformation are