The correct answer is polymerase chain reaction (PCR).
PCR is a technique that uses a special enzyme called DNA polymerase to copy a specific segment of DNA repeatedly. PCR can produce millions of copies of a DNA fragment from a very small amount of starting material. PCR is useful for many applications, such as DNA fingerprinting, gene cloning, genetic testing, and forensic analysis.Some of the other processes mentioned in the question are:Restriction digest: a process that uses enzymes called restriction endonucleases to cut DNA molecules at specific sequences.Gel electrophoresis: a process that separates DNA fragments based on their size and charge by applying an electric current to a gel matrix.Transformation: a process that introduces foreign DNA into a cell, usually a bacterium, by using a vector such as a plasmid.