Which Does Not Occur During the Hydrolysis of RNA by RNase

Multiple Choice

Which does not occur during the hydrolysis of RNA by RNase A?

A) Covalent catalysis involving a bond between a pyrimidine and a lysine of RNase A.
B) Acid-base catalysis to cleave the phosphodiester bond.
C) Abstraction of a proton from the 2'-hydroxyl group by histidine.
D) Transition-state stabilization of a pentavalent phosphorous atom.