DNA is transcribed by some viral RNA using the enzyme

The correct option is B Reverse transcriptase
Reverse transcriptase is a common name for an enzyme that functions as an RNA-dependent DNA polymerase. They are encoded by retroviruses, where they copy the viral RNA is transcribed into DNA into host cells. In the process, virus use reverse transcriptase enzyme and transcribe single-stranded RNA from their own RNA copy and both the RNA is bind together to form DNA and such DNA is called as c DNA.