Which of the following compounds is most reactive towards nucleophilic addition reactions?
Correct option is B.
Aldehydes are generally more reactive than ketones in the nucleophilic reaction due to steric and electronic reasons. Benzaldehyde is less reactive than ethanal as the polarity of the carbonyl group is reduced in benzaldehyde due to resonance.
So, Benzaldehyde is most reactive towards nucleophilic addition reactions.
Hence, Option "B" is the correct answer.