In the cannizaro reaction given below $2\mathrm{PhCHO}\stackrel{{\mathrm{OH}}^{-}}{⟶}{\mathrm{PhCH}}_2\mathrm{OH}+{\mathrm{PhCO}}_2^{-}$ The slowest step is

The attack of OH^- at the carbonyl group

The transfer of hydride to the carbonyl group

The abstraction of proton from the carboxylic group

Deprotonation of PhCH₂OH .