The cutting of DNA at specific locations became possible with the discovery of Probes, Selectable markers, Ligases, Restriction enzymes?

Genetic engineering is possible because of special enzymes that cut DNA. These enzymes are called restriction enzymes or restriction endonucleases. Restriction enzymes are proteins produced by bacteria to prevent or restrict invasion by foreign DNA. They act as DNA scissors, cutting the foreign DNA into pieces so that it cannot function. These enzymes are routinely used for DNA modification in laboratories and are a vital tool in molecular cloning. So, the correct answer is 'Restriction enzymes'