Which of the following best explains mechanisms by which histones interact with DNA?
A. Histone core proteins interact with the main groove of DNA by the helix-turn-helix-turn-helix motif.
B. Interactions between histone core proteins and DNA happen by positive and negative charge interactions at the minor groove.
C. The N-terminal tails of histone core proteins interacts with the main groove of the DNA double helix.
D. Histone core proteins are covalently bound to the DNA double helix.