Unpleasant smelling carbylamines are formed by heating alkali and chloroform with

In the following reaction,the suitable starting reagent $P$ is

$CH_3-CH_2-NH_2 \xrightarrow{CHCl_3, KOH} \text{Product}$

The final product $C$,obtained in the following reaction sequence,would be:
$p$-Toluidine $\xrightarrow{Ac_2O} A$ $\xrightarrow{Br_2/CH_3COOH} B$ $\xrightarrow{H_2O/H^+} C$

The product $C$ of the following reaction sequence is:

Select the percentage in which these amine derivatives are formed in the reaction mixture along with the reason for the nitration of aniline: