Alvin is studying a model of the chemical structure of a common nucleic acid. He observes that the nucleic acid consists of four nitrogenous
bases: adenine (A), cytosine (C), guanine (G), and uracil (U).
Alvin's observation most strongly supports which of these conclusions?
A. The nucleic acid is a form of RNA, and is not DNA.
B. The nucleic acid is either mRNA or rRNA, but not tRNA.
C. The nucleic acid is either RNA or DNA.
D. The nucleic acid is DNA, and is not RNA.