Answer:
The correct answer would be option C.
DNA (deoxyribonucleic acid) is a polymer of nucleotides. It is composed of the same components which are; deoxyribose sugar, a phosphate group, same set of nitrogenous bases (adenine, guanine, cytosine, and thymine).
The difference in the nucleotide sequence of the DNA is the main reason for the variation observed in the genome of different organisms.
The change in the nucleotide sequence of DNA codes for different proteins and thus, different phenotypes in different organisms.