Final answer:
DNA is made up of two strands that coil around each other to form the characteristic double helix, with each strand being composed of nucleotide molecules.
Step-by-step explanation:
The question 'How many molecules are there in DNA?' refers to the number of distinct polymers or strands that compose the DNA double helix structure. Given the options, the answer is B) Two. DNA is comprised of two long polymers called strands that are coiled around each other to form a double helix. Each of these strands is made up of smaller units called nucleotides, which are molecules themselves comprising a nitrogenous base, a phosphate group, and a five-carbon sugar called deoxyribose. These two strands run in opposite directions and are bonded together by hydrogen bonds between the complementary bases of the nucleotides: adenine with thymine and guanine with cytosine.