Why Is the Imidazole R-Group of Histidine a Particularly Versatile

Why is the imidazole R-group of histidine a particularly versatile amino acid side chain in terms of its involvement in enzymatic reaction mechanisms?

A) It is strongly involved in specific acid-base catalysis.
B) It acts as a strong electrophile.
C) It disrupts H-bonds and stabilizes exposed peptide residues.
D) It acts as a strong nucleophile as well as a general acid or base.
E) It contains a high energy phosphate bond.