Aniline reacts with which of the following to form a Schiff base?

The product of the reaction $image \xrightarrow[{HCl}]{{NaNO_2}} (A)$ is:

Identify the final product $D$ in the following reaction sequence: $CH_3CH_2Br$ $\xrightarrow[\Delta]{Aq. KOH} A$ $\xrightarrow[\Delta]{KMnO_4/H^+} B$ $\xrightarrow[\Delta]{NH_3} C$ $\xrightarrow[alkali]{Br_2} D$

The final product $[B]$ is :

In the following reaction,the product $(A)$ is a yellow dye. Identify $(A)$.

Carbylamine is liberated when $.....$ is heated with chloroform and alcoholic potash.