An organic compound $\left[\mathrm{A}\right]\left({\mathrm{C}}_4{\mathrm{H}}_{11} \mathrm{N}\right)$, shows optical activity and gives ${\mathrm{N}}_2$ gas on treatment with ${\mathrm{HNO}}_2$. The compound $\left[\mathrm{A}\right]$ reacts with ${\mathrm{PhSO}}_2\mathrm{Cl}$ producing a compound which is soluble in $\mathrm{KOH}$. The structure of $\mathrm{A}$ is :

In the following reaction, ‘$\mathrm{A}$’ is

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): $\alpha$-halocarboxylic acid on reaction with dil. ${\mathrm{NH}}_3$ gives good yield of $\alpha$-amino carboxylic acid whereas the yield of amines is very low when prepared from alkyl halides.

Reason (R): Amino acids exist in zwitter ion form in aqueous medium.

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