Which of the following describes the directionality seen in nucleic acids?

A)most polynucleotides have an unreacted 5' hydroxyl group
B)all polynucleotides have an unreacted 2' hydroxyl group
C)most polynucleotides have a phosphate group on the 5' end
D)sequences of polynucleotides are generally written from 3' on the left to 5' on the right
E)none of the above