The right answer is A.Transcription uses uracil.
The genes carried by the DNA will be encoded in another form: messenger RNA, during a process called "transcription".
The DNA and RNA molecules are chemically very close, but the second has an extra oxygen (in red on the right of the letters) on the sugars (riboses) that make up its nucleotides (the DNA actually contains deoxyribose). In addition, the thymine (T) of DNA is replaced by uracil (U) in RNA.
