With Respect to Histone Modifications, Which, If Any, of the Following

Multiple Choice

With respect to histone modifications, which, if any, of the following statements, is true?

A) histone acetylation always means adding an acetyl group to the side chain of a lysine residue.
B) in histone acetylation each lysine of the histone is acetylated.
C) in histone phosphorylation a phosphate group is transferred to the side chain of a serine .
D) in histone methylation it is the DNA that coils around a nucleosome that is methylated, not the histone itself.