The products $A$ and $B$ formed in the following reaction scheme are respectively:

Identify the tertiary amine from the following.

The decreasing order of basicity is:
$(1) \ CH_3CONH_2$
$(2) \ CH_3CH_2NH_2$
$(3) \ PhCH_2CONH_2$

Given below are two statements:
Statement $I$: Pure Aniline and other arylamines are usually colourless.
Statement $II$: Arylamines get coloured on storage due to atmospheric reduction.
In the light of the above statements,choose the most appropriate answer from the options given below:

The correct order of basic strength of methyl-substituted amines in an aqueous medium is:

Explain: Acetylation.