Answer:
C
Step-by-step explanation:
The 5'end of the molecule is where the phosphate group is attached to the fifth carbon of the deoxyribose sugar. The 3'end is where the phosphate group is attached to 3rd carbon atom of the deoxyribose sugar.the rungs of the ladder are the complementary base pairs joined by hydrogen bonds.
anything that is a base make up the "rungs" of the ladder