Final answer:
Thymine (C) is the correct answer to the question of which pyrimidine is found in DNA, distinguished from the purines adenine and guanine by its single-ring structure. Therefore, the correct option is C.
Step-by-step explanation:
The pyrimidine found in DNA is thymine (C). In the context of nucleic acids, there are five nitrogen bases categorized either as purines or pyrimidines. While adenine (A) and guanine (G) are classified as purines, cytosine (C), thymine (T), and uracil (U) are classified as pyrimidines. The primary structure of a purine consists of two carbon-nitrogen rings, whereas a pyrimidine has a single ring structure. In DNA, thymine pairs with adenine, which is one of the key aspects of complementary base pairing. It's important to note that while DNA contains thymine, RNA contains uracil (U) instead, which also pairs with adenine.