I would say <span>C. being injected into the cell is the right answer</span>
The correct answer is uracil.
<span>Uracil is one of the pyrimidine nucleotide bases which is the component of nucleic acid-RNA. In RNA, uracil binds to adenine via two hydrogen bonds (complementary binding). Uracil is not found in DNA, it is replaced by thymine because it is thymine’s demethylated form.</span>