Wrong. Adenine, Cytosine, Uracil, and Guanine are the nitrogenous bases of RNA, they are not nucleotides. A nucleotide is a nucleoside with phosphate attached. A nucleoside is the base attached to ribose on the 1’ carbon of the ribose ring.
Not nucleotides, but purine and pyrimidine bases:
Cytosine is an RNA base, it is not a nucleoTIDE. The whole structure with the base (in red) atached to ribose (together making the part circled in bright blue), with monophosphate attached to the 2’ and ‘3 carbons of the ribose ring(dark blue), is the “legit” RNA nucleotide called Cytidine-2’3’-cyclic monophosphate, and it actually does exist in living cells:
