The correct option is A Recombinant DNA techniques
A transgenic, or genetically modified, organism is one that has been altered through recombinant DNA technology, which involves either the combining of DNA from different genomes or the insertion of foreign DNA into a genome.
Heavy isotope labelling - involves the use of non-radioactive isotopes that can act as a tracers used to model several chemical and biochemical systems.
X-ray diffraction - a scattering of X-rays by the atoms of a crystal that produces an interference effect so that the diffraction pattern gives information on the structure of the crystal or the identity of a crystalline substance.
Hybridisation - to find the gene of interest in a genome