What is the major alkene formed in the following Hofmann elimination?

Identify $A$ and $B$ in the following reactions:

What is the correct order of basicity for the given amines in a chlorobenzene medium?
$(A)$ $CH_3CH_2NH_2$
$(B)$ Cyclohexylamine
$(C)$ $N$-Methylpiperidine
$(D)$ Pyrrolidine

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:

Consider the following sequence of reactions: $C_2H_5-Br$ $\xrightarrow{AgCN} A$ $\xrightarrow{H_2/Ni} B$. Product $B$ is:

Compound $III$ is
$\xrightarrow[{ii)\,CuCl/HCl}]{{i)\,HNO_2\,(0 - 5\,^oC)}}I$ $\xrightarrow{{Sn/HCl}}II$ $\xrightarrow[{ii)\,H_3PO_2 + H_2O}]{{i)HNO_2\,(0 - 5\,^oC)\,}}III$