Answer: D - all of the above
Step-by-step explanation:
Cytosine (C) is paired with Guanine (G) according to the base pair rule just as Adenine (A) is paired with Thymine (T).
The sugar in DNA is deoxyribose which is a modified form of ribose(also sugar). It simply is a ribose sugar which has lost an oxygen atom hence “deoxyribose”. Deoxyribose is one of the components that make up the DNA backbone.
Hydrogen bonds exist between bases. The importance of these hydrogen bonds is to hold the complementary strands of DNA together.