Which of the following is the weakest base?

The increasing order of the $pK_b$ of the following compounds is:

$C_{6}H_{5}NO_{2}$ $\xrightarrow{Sn+HCl} A$ $\xrightarrow{C_{6}H_{5}N_{2}^{\oplus}Cl^{\ominus}} P$
(Yellow coloured compound)
Consider the above reaction,the Product "$P$" is:

Reduction of nitrobenzene with $Zn$ and alcoholic $KOH$ solution results in the formation of the following compound:

The product of the mustard oil reaction is:

Product of the reaction is