The answer is phosphodiester bond.
That is the bond that is formed between the 5' phosphate group (PO₄ ) of one nucleotide and the 3' hydroxyl (OH) group of the adjacent nucleotide is called phosphodiester bond.
Nucleotide orientation is 5′-to-3′ that is 5' phosphate group (PO₄ ) of one nucleotide and the 3' hydroxyl (OH) group of the adjacent nucleotide .The length of DNA chain doesn't matter for this orientation.
