According to Chargaff's Rule, which base pairing is correct?

According to Chargaff's Rule, which base pairing is correct?

• A. A equals G and T equals C
• B. A equals T and G equals U
• C. A equals T and G equals C; base pairing across from one another; two strands also called base pairing.
• D. A equals U and G equals C

Answer: (C)

Chargaff's Rule says that in DNA the amount of adenine equals thymine and the amount of guanine equals cytosine. This leads to complementary base pairing across the two strands: adenine pairs with thymine, and guanine pairs with cytosine. The option reflects both A = T and G = C and notes base pairing across from each other in a two-stranded molecule. That alignment is exactly how DNA strands are organized. The other choices mix in incorrect pairings (A with G), introduce uracil (found in RNA, not DNA), or suggest A pairs with U, which isn’t how DNA pairs.

Chargaff's Rule says that in DNA the amount of adenine equals thymine and the amount of guanine equals cytosine. This leads to complementary base pairing across the two strands: adenine pairs with thymine, and guanine pairs with cytosine. The option reflects both A = T and G = C and notes base pairing across from each other in a two-stranded molecule. That alignment is exactly how DNA strands are organized. The other choices mix in incorrect pairings (A with G), introduce uracil (found in RNA, not DNA), or suggest A pairs with U, which isn’t how DNA pairs.