An important characteristic in the mechanism of this reaction is the formation of a tetrahedral intermediate which is the result of
a. the alcohol attacking the 2-phenylacetic acid with the subsequent loss of a proton.
b. protonation of the ethanol by H2SO4.
c. protonation of the carbonyl oxygen of the 2-phenylacetic acid.
d. protonation of the hydroxyl group of the 2-phenylacetic acid.