Aldehyde and ketones are specially susceptible susceptible to nucleophile addition because carbonyl group (due to electronegatvity different between carbon and oxygen).

Positive charge on carbon makes it reactive towards the nucleophile. This addition is catalysed by acid. Reactivity of carbonyl compound towards nucleophilic addition increases in the electron deficience at carbonyl carbon. Thus, (-I.E.) group increase while (+I.E.) groups decrease the reactivity of carbonyl compound
Carbonyl compounds show nucleophilic addition with:

Options

A. HCN
B. `NaHSO_(3)`
C. `(CH_(3)OH+HCl)`
D. all of these

Answer

D