One solenoid composed of:–

In the nucleus, DNA is wrapped around positively charged proteins called Histones. Two histone H2A-H2B dimers, two histone H3 proteins, and two histone H4 proteins together form an octamer of histones around which the DNA can be wrapped. The first stage of the packaging looks like a ‘beads on a string’ model and is of 11nm. Another type of histone protein called H1 binds to the sites where DNA enters and exits the nucleosome. Each octamer wrapped with DNA is called a nucleosome. In a solenoid structure, the nucleosomes are stacked and are connected by bent linker DNA. The nucleosomes are positioned with the histone H1 proteins facing toward the center and at this position, they form a polymer. A helix is formed containing 6 nucleosomes in each turn.
Hence, the correct option is B.