Answer:
The correct answer would be B. complementary.
The two strands of the DNA molecule are always complementary to each other.
Complementary means that purine will always make a bond with a pyrimidine.
More specifically, adenine always makes a bond with thymine and guanine always makes a bond with cytosine.
Due to this nature and semi-conservative replication, the two strands of DNA produced during replication are copies of each other.