The major product of the following reaction is :

The major product of the following reaction is :

The compound $\mathrm{A}$ and $\mathrm{B}$ in the following reaction are, respectively, :

The major product of the following reaction:

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

$2$-Chloro-$2$-methylpentane on reaction with sodium methoxide in methanol yields.