Which of the following best describes a metaphase chromosome?

a.
a double strand of dna with its nucleosomes wound up once around itself to form a thicker structure

b.
an area in the nucleus of a eukaryotic cell where ribosomes are made from rna and protein

c.
a looped chromatin fiber folded up on itself again

d.
a dna molecule in the process of doubling itself to make another identical one