Final answer:
DNA is not a component of a nucleotide; instead, nucleotides form DNA. Each nucleotide consists of a nitrogenous base, a pentose sugar, and phosphate groups.
Step-by-step explanation:
The component that is NOT a part of a nucleotide is option d. DNA. Nucleotides themselves are the building blocks of nucleic acids, such as DNA and RNA. Each nucleotide is composed of three main components: a nitrogenous base, a pentose sugar, and one or more phosphate groups. The pentose sugar could be either deoxyribose, in the case of DNA, or ribose for RNA. The nitrogen-containing bases are divided into purines (adenine and guanine) and pyrimidines (cytosine, thymine, and uracil). However, DNA itself is not a component of a nucleotide but rather a macromolecule that is made up of many nucleotides joined together through phosphodiester bonds.