What is the color of the precipitate formed when aniline reacts with $HNO_2$ at low temperature,followed by treatment with an alkaline $\beta$-naphthol solution?

When $(P)$ undergoes Hoffmann exhaustive methylation (twice) then the product obtained will be

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:

The hydrolysis of alkyl isocyanides $(R-CH_2-NC)$ gives:

Which reaction is known as the Schotten-Baumann reaction?

Amines behave as