Answer:
The correct answer will be option-C.
Step-by-step explanation:
Each DNA molecule exists in helical shape made by two strands of nucleotides. Each nucleotide is composed of a five-carbon sugar, a phosphate group and nitrogenous bases.
The sugar-phosphate unit bond via the phospho-diester bond and form the backbone of the DNA. The phosphate functional group is acidic in nature as it donates the proton while the formation of the phosphodiester bond which provides DNA with the acidic nature.
Thus, Option-C is the correct answer.