Identify the product $B$ in the following reaction: $CH_3Br \xrightarrow{KCN} A \xrightarrow{Na / C_2H_5OH} B$

An aromatic compound '$A$' on treatment with aqueous ammonia and heating forms compound '$B$',which on heating with $Br_2$ and $KOH$ forms a compound $C$ of molecular formula $C_6H_7N$. The structures of compound $A, B$ and $C$ are respectively:

Which of the following reactions occurs by the removal of a $-CO-$ group from an amide?

The product $(C)$ will be

Consider the following sequence of reactions. Identify $A, B, C$.

How many primary amines are possible for the formula $C_4H_{11}N$?