The reaction of cyclohexanone with dimethylamine in the presence of a catalytic amount of an acid forms a compound if water is continuously removed during the reaction. The compound formed is generally known as:

Reaction of $R-CONH_2$ with a mixture of $Br_2$ and $KOH$ gives $R-NH_2$ as the main product. The intermediates involved in this reaction are :-
$(A)$ $R-CONHBr$
$(B)$ $R-NH-Br$
$(C)$ $R-N=C=O$
$(D)$ $R-CONBr_2$

The correct sequential order of the reagents for the given reaction is:

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:

$Ph-C \equiv CH$ $\xrightarrow[Excess]{HCl} X$ $\xrightarrow{KOH (aq.)} Y$ $\xrightarrow{CH_3-CH_2-NH_2} Z,$
$Z$ is known as

Identify the correct decreasing order of basic strength of methyl-substituted amines in an aqueous solution.