The order of reactivity of carbonyl compounds for nucleophilic addition is

Carbonyl carbon which is more electron deficient, shows more reactivity towards nucleophilic addition reaction. Presence of −R− or −Ar groups, decrease the reactivity of carbonyl carbon because they are electron releasing groups. More these groups present, less is the reactivity.

Hence, the correct order is:

H₂C = O > RCHO > ArCHO > R₂C = O > Ar₂C = O