The best answer would be:
A. DNA is being transcribed into mRNA.
If you'd like to know why:
In the image shown, you can see the BLUE strands and the RED strand. The Blue strand is DNA and the Red strand is mRNA. What is happening in the picture is TRANSCRIPTION. It is the process of making an RNA copy of the DNA strand to create proteins based on the DNA strand.
The GREEN blob is most likely RNA polymerase. Its job is to synthesize or make a complementary RNA strand of the DNA by assembling nucleotides to form an RNA strand based on the DNA template.