In the Cannizzaro reaction given below:
`2Ph-CHO overset(overset(Θ)OH)rarrPh-CH_(2)OH+PhCO_(2)^(-)` the slowest step is:
A. the attack of _OH at the carbony1 group
B. the transfer of hydride to the cardony1 group
C. the abstraction of proton from the carboxy,ic acid
D. the deprotonation of `PH-CH_(2)OH`