How many molecules of methyl iodide are required to obtain tetramethyl ammonium iodide from dimethyl amine?

The compound obtained by the reaction between primary amine and aldehyde is:

The decreasing order of the basic character of the following amines and ammonia is:

The reaction between a primary amine,chloroform and a few drops of alcoholic $KOH$ is known as:

Identify $Z$ in the following sequence of reactions.

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: