Regarding the Structure of Bases in Nucleic Acids, Which, If

Multiple Choice

Regarding the structure of bases in nucleic acids, which, if any, of the following statements is incorrect?

A) Pyrimidines have a single heterocylic ring consisting of four carbon atoms plus two nitrogen atoms that are linked to the same carbonyl (-C=O) group
B) Purines have two heterocyclic rings, each with two nitrogen atoms
C) Thymine = 5-methyluracil.
D) Purines carry an amino group, unlike pyrimidines