What is the oldest form of genetic engineering? Selective breeding hybridization cloning recombinant DNA

The correct answer is option Selective breeding.

The selective breeding is a technique, in which two different individuals having a specific desired phenotype is present. Both the individuals have different desired phenotype. They are crossed together, so that a progeny having both type of phenotype or trait is obtained.

Hybridization, cloning and recombinant DNA technology emerged years after the introduction of selective breeding. These are very new tools used in DNA technology, whereas, selective breeding was from ancient times.