PLEASE HELP ME ASAP BECAUSE IT IS DIFFICULT TO UNDERSTAND. Explain it for me.

C.

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 :)

thinking it would be d not too sure but i think it's right

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.