How Are Purines Distinguished from Pyrimidines

Multiple Choice

How are purines distinguished from pyrimidines?

A) Purines are derived from a pair of fused C-N rings, while pyrimidines are derived from a single C-N ring.
B) Pyrimidines are derived from a pair of fused C-N rings, while purines are derived from a single C-N ring.
C) Purines have a carbon-containing ring, while pyrimidines have a nitrogenous ring.
D) Pyrimidines have a carbon-containing ring, while purines have a nitrogenous ring.
E) Purines are found only in DNA, while pyrimidines are found only in RNA.