Histones are enriched with -

The correct answer is Lysine & Arginine.

Explanation:
Histones are highly alkaline proteins found in eukaryotic cell nuclei. Their primary function is to package and order the DNA into structural units called nucleosomes. DNA molecules carry a net negative charge along their sugar-phosphate backbone because of the phosphate groups.

To bind efficiently and tightly to the negatively charged DNA, histones must possess a net positive charge. This positive charge is provided by an abundance of basic amino acids. Among the standard amino acids, lysine and arginine contain basic side chains that are positively charged at physiological pH.

Therefore, histones are enriched with lysine and arginine residues, enabling them to form strong electrostatic interactions with the negatively charged DNA double helix.