Histones are proteins that regulate gene expression by binding to DNA and controlling which regions are exposed to be expressed. Histones bind to DNA at a neutral pH via their positively charged lysine residues, but acetylation of histones leads to the dissociation of the DNA-Histone complex. Covalent modification of lysine's ammonium group by acetylation results in an overall _______________ charge of the histone binding region.

• A. Positive.
• B. Neutral.
• C. Negative.