Aniline does not undergo

In the reaction,

P, Q and R respectively are

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

$$\begin{aligned} & R-X+\mathrm{AgCN} \longrightarrow A+\mathrm{Ag} X \\ & R-X+\mathrm{KCN} \longrightarrow B+\mathrm{KX} \end{aligned}$$

In carbylamine test for primary amines the resulting foul smelling product is