Answer:
Single nucleotide pair.
Explanation:
DNA is present as genetic material in all the living organism except some viruses. DNA is made of nitrogenous base, pentose sugar and the phosphate group.
DNA can be hydrolyzed further into the single sub units of the nucleotide. The single nucleotide pair unit of the DNA consists of a single nucleotide that can not be broken down further. Mutation or even recombination is not enough for the division of single nucleotide pair.
Thus, the correct answer is option (d).
