Gel electrophoresis is a way to isolate fragments of DNA depending on its size. Nuclear transfer is a type of cloning that clear away DNA from the unfertilized egg and into the nucleus where the cloned DNA is present. Reverse transcriptase is used to produce cDNA copy of mRNA.
Polymerase chain reaction (PCR) is capable of producing many copies of DNA even in small amounts of sample. With this technology, there is the possibility of generating thousands to millions of DNA copies of a specific section of DNA out of a small amount of DNA. PCR is being used as a common tool in medical and biological research lab.
Answer - Option C - Polymerase chain reaction