Aldehydes are more reactive than ketones due to the steric factor, the heavy alkyl groups on both the side of ketone hinder the approach of a nucleophile to the carbonyl carbon (carbon atom double-bonded to an oxygen atom).

Thus, option (ii) is wrong.

The polarity of the carbonyl group is reduced when it is attached to an aromatic ring due to its involvement in resonance. Thus their reactivity towards nucleophilic attack reduces.

Thus, option (iii) and (iv) are wrong.

Thus, option (i) is most reactive towards nucleophilic addition.