(N/A) The carbon atom of the carbonyl group of $benzaldehyde$ is less electrophilic than the carbon atom of the carbonyl group present in $propanal$.
In $benzaldehyde$,the phenyl group is attached to the carbonyl carbon,which provides resonance stabilization to the carbonyl group. This resonance effect delocalizes the positive charge on the carbonyl carbon,thereby reducing its electrophilicity.
Additionally,the phenyl group exerts a steric hindrance that makes the approach of a nucleophile more difficult compared to the smaller alkyl group in $propanal$.
Therefore,$benzaldehyde$ is less reactive than $propanal$ towards nucleophilic addition reactions.