What is obtained by the reaction of acetamide with bromine and caustic soda?

Aniline is treated with $NaNO_2 + HCl$ at low temperature to form:

Consider the following set of reactions. What are $A$ and $B$ respectively?
$Y \xleftarrow{B} C_6H_5CN \xrightarrow{A} X$
($Y$ reacts with $2,4-DNP$)
($X$ dissolves in dil. $HCl$)

Which of the following yields a primary amine upon acidic hydrolysis?

Which of the following nitrogen compounds gives a primary amine upon reaction with $Br_2$ and strong $KOH$ (Hofmann bromamide degradation reaction)?

Which of the following amines can be prepared by Gabriel phthalimide reaction?