Understanding ambident nucleophiles:
Ambident nucleophiles are molecules that can donate electrons from two different atoms.
Option A (CN-) is an ambident nucleophile because it can donate electrons from the carbon or nitrogen atom.
Option C (NO2-) is an ambident nucleophile because it can donate electrons either from the nitrogen or the oxygen atom.
Option B (CH3COO-), Option D (CH3O-), and Option E (NH3) are not ambident nucleophiles.
Thus, the correct answer is option (2).