Answer:
B. as segments of the rails
Step-by-step explanation:
If we look at what makes the backbone of a DNA strand,we will see that it is made up of alternating phosphate and sugar. The sugar that is found in the DNA ( 2-deoxyribose) , also known as a pentose five-carbon sugar joins with the phosphate portion as segments of the rails to form a phosphodiester bonds between the third and fifth carbon atoms of adjacent sugar rings.