In methanol (protic solvent), nucleophilicity is determined by basicity and solvation effects. Smaller ions are heavily solvated by the protic solvent, reducing their effective nucleophilicity.
(ethoxide) is the strongest nucleophile as it is less solvated and highly basic.
(phenoxide) is weaker due to resonance stabilization by the benzene ring.
is highly solvated despite high basicity, reducing its nucleophilicity significantly.
is the best nucleophile because it is the largest ion and least solvated in methanol.

The correct order is .