Which of the following describes the pairing of bases in DNA?

The correct option describes the complementary base pairing in DNA accurately. In the structure of DNA, adenine (A) pairs specifically with thymine (T) through two hydrogen bonds. This pairing is fundamental to the double helical structure of DNA and plays a crucial role in DNA replication and transcription.

In contrast, uracil (U) is not found in DNA; it is only present in RNA, where it pairs with adenine. Therefore, the option that includes adenine pairing with uracil does not apply to DNA pairing. Cytosine (C) pairs with guanine (G), not thymine, which also highlights a misunderstanding of the DNA pairing rules. Hence, adenine's pairing with thymine is the hallmark of complementary base pairing in the DNA molecule, ensuring that genetic information is accurately copied and passed on during cell division.