Which carbonyl group is most reactive for $NAR$ (Nucleophilic Addition Reaction)?

Which of the following compounds would undergo Cannizzaro's reaction?

Which of the following compounds gives the $2,4-DNP$ test?

Which of the following is $D$ in the given reaction sequence?
$(CH_3)_3C-CH_2OH$ $\xrightarrow{PCC} B$ $\xrightarrow{Conc. NaOH} A + C$ $\xrightarrow{NaOH/CaO, \Delta} D$

The product $(A)$ is:

Which of the following compounds would undergo aldol condensation,which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.
$(i)$ Methanal $(ii)$ $2-$Methylpentanal $(iii)$ Benzaldehyde $(iv)$ Benzophenone $(v)$ Cyclohexanone $(vi)$ $1-$Phenylpropanone $(vii)$ Phenylacetaldehyde $(viii)$ Butan$-1-$ol $(ix)$ $2,2-$Dimethylbutanal