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. $NH_3$ 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:

• A
  Both $(A)$ and $(R)$ are correct and $(R)$ is the correct explanation of $(A)$.
• B
  Both $(A)$ and $(R)$ are correct but $(R)$ is not the correct explanation of $(A)$.
• C
  $(A)$ is correct but $(R)$ is not correct.
• D
  $(A)$ is not correct but $(R)$ is correct.