The correct option is D Gene manipulation
Gene manipulation is also sometimes called the genetic engineering. It is a general term for any method which manipulates with the genetic material. Gene manipulation includes gene splicing, use of recombinant DNA, forming of the monoclonal antibodies or PCR (polymerase chain reaction). Genetically engineered giant mice illustrate the expression of foreign genes in mammalian cells. Giant mice were produced by introducing the gene for rat growth hormone into a fertilized mouse egg.