Deoxyribonucleic acid (DNA) is made of two chains of nucleotides, each of the nucleotides is composed of a phosphate, a deoxyribose, and a nitrogenous base.
Each chain of nucleotides is held together by covalent bonds between the sugar of a nucleotide and the phosphate of the next, while the two chains form a double helix held together by hydrogen bonds between the nitrogenous base.
So, when ligase is connecting nucleotides together, is connecting sugar to phosphate (E is the right answer)