Which reagent reacts with acetamide to produce methylamine?

An organic compound $A$ on treatment with $NH_3$ gives $B$,which on heating gives $C$. $C$ when treated with $Br_2$ in the presence of $KOH$ produces ethyl amine. Compound $A$ is:

Identify $B$ in the following conversion: $CH_3-I$ $\xrightarrow{KCN} A$ $\xrightarrow{Na / C_2H_5OH} B$

Write chemical equations for the following conversions:
$(i)$ $CH_3-CH_2-Cl$ into $CH_3-CH_2-CH_2-NH_2$
$(ii)$ $C_6H_5-CH_2-Cl$ into $C_6H_5-CH_2-CH_2-NH_2$

$C_2H_5Br$ $\xrightarrow{AgCN} X$ $\xrightarrow{\text{Reduction}} Y$. Here $Y$ is

The major product of the following reaction is: