The product formed from the following reaction sequence is?

Consider the following sequence of reactions:
$C_6H_5NH_2$ $\xrightarrow{NaNO_2, 0-5^{\circ}C} 'A'$ $\xrightarrow{N,N-\text{Dimethylaniline}} 'B'$
The product $B$ is

In the reaction $C_6H_5CHO + C_6H_5NH_2 \to C_6H_5N=CHC_6H_5 + H_2O$,the compound $C_6H_5N=CHC_6H_5$ is known as

Aniline reacts with mixed acid (conc. $HNO_3$ and conc. $H_2SO_4$) at $288 \ K$ to give $P$ $(51 \%)$,$Q$ $(47 \%)$ and $R$ $(2 \%)$. The major product$(s)$ of the following reaction sequence is (are):
$R$ $\xrightarrow[2) Br_2, CH_3CO_2H]{1) Ac_2O, \text{pyridine}}$ $\xrightarrow{3) H_3O^+}$ $\xrightarrow{4) NaNO_2, HCl / 273-278 \ K}$ $\xrightarrow{5) EtOH, \Delta}$ $\xrightarrow{6) Sn/HCl}$ $\xrightarrow{7) Br_2/H_2O \text{ (excess)}} \text{Major Product}$

On heating an aliphatic primary amine with chloroform and ethanolic potassium hydroxide,the organic compound formed is:

The strongest conjugate acid will result from: