Which one of the following compounds gives a secondary amine on reduction?

Consider the following sequence of reactions: $HCHO$ $\xrightarrow[dil. H_2SO_4]{NaCN} A$ $\xrightarrow[Pt]{H_2} B$. The product $(B)$ is:

Indicate which nitrogen compound amongst the following would undergo Hofmann's reaction (i.e.,reaction with $Br_2$ and strong $KOH$) to furnish the primary amine $(R-NH_2)$.

What are $A$ and $B$ in the following reactions?
$A \xrightarrow{H_2 / Ni} R-CH_2-NH_2 \xleftarrow[ii) H_2O]{i) LiAlH_4} B$

What will be the product $A$ in the reaction given below?

Aniline is not the major product in one of the following reactions. Identify that reaction.