The Bases of Nucleic Acids Are Purines or Pyrimidines

Multiple Choice

The bases of nucleic acids are purines or pyrimidines.Which statement contrasting purines and pyrimidines is true?

A) Purines include the bases cytosine and thymine, whereas pyrimidines include the bases adenine and guanine.
B) Pyrimidines are found in RNA, whereas purines are found in DNA.
C) Purines are double-ring structures, whereas pyrimidines are single-ring structures.
D) Purines have only single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure.
E) Purines consist of hydrogen, carbon, oxygen, and nitrogen, whereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen.