Which PCR Step Synthesizes Complimentary DNA Strands

Question

Which PCR step synthesizes complimentary DNA strands?
A) Cool DNA to between 50° C and 65° C.
B) Add DNA polymerase and nucleotides at 72° C.
C) Add primers.
D) Heat target DNA to 94° C.

Accepted Answer

The step where DNA polymerase and nucleotides are added at 72° C is the extension/elongation phase of PCR, where complementary DNA strands are synthesized.