Nucleophilic addition reaction will be most favoured in

Aldehydes are more reactive than ketones due to $+\mathrm{I}$ effect of $-\mathrm{CH}_{3}$ group. There are two $-\mathrm{CH}_{3}$ group in acetone which reduces +ve charge density on carbon atom of carbonyl group. More hindered carbonyl group becomes less reactive. So in the given case $\mathrm{CH}_{3} \mathrm{CHO}$ is the right choice.