The correct option is D It remains active at high temperature
Polymerase Chain Reaction (PCR) is used to amplify a DNA segment or to synthesize in vitro the multiple copies of a gene (or DNA) of interest, using two sets of primers and the enzyme DNA polymerase. This enzyme is isolated from a bacterium Thermus aquaticus and it remains active during the high temperature, but high temperature induces denaturation of double-stranded DNA.
Ligase is used to ligate introduced DNA.DNA
Antibiotic resistance genes serve as a selectable marker.
DNA polymerase is isolated from a bacteria. e.g. Thermostable DNA polymerase (Taq Pol Ι) from the bacteria Thermus aquaticus has been widely used in PCR