Answer:
C.
Step-by-step explanation:
For mRNA strands, there are four letters used in their code. A (adenine), U (Uracil), G (guanine), and C (cytosine.)
For RNA, it is the same, but the Uracil is replaced with Thymine (T).
A always pairs with U.
G always pairs with C.
YOUR QUESTION:
The scientist's strand code is has to convert the Thymine to Uracil since it is RNA instead of mRNA.
Hopefully this somewhat helped :)