Answer:
C.dNTPs.
Step-by-step explanation:
The dNTPs (deoxynucleoside triphosphate) are made of a 5-carbon sugar (a deoxyribose), three phosphate groups and a nitrogenous base (adenine, thymine, guanine or cytosine).
They are the monomers of DNA used in PCR reactions to synthesize the new strands. There are four dNTPs, each containing a different nitrogenous base (dATP, dTTP, dGTP and dCTP). The DNA polymerase will extend the primers by adding a dNTP complementary to the template strand during the elongation phase of PCR.