Which of the following carbonyl compound is most reactive towards nucleophilic addition reactions

Rate of Nucleophilic Addition α  electrophilicity of carbonyl carbonReactivity of Ketones < AldehydesDue +I effect and steric hindrance Ketones are less reactive+I effect of two alkyl groups decreases the electrophilicity of carbon.  Presence two alkyl groups on carbonyl carbon increases the steric hindrance.∴  Most reactive unsubstituted carbonyl compound towards nucleophilic addition is HCHO.