Read the short text. Complete the sentence with the correct part.

So, the basic idea of genetic engineering is to put a gene of interest, that produces useful proteins, into another piece of DNA to create recombinant DNA. This DNA is combined from two or more sources.

The recombinant DNA purpose for genetic engineering is to ...

• make recombinant DNA using the technology of a gene of interest.
• create useful proteins using the technology of a gene of interest.
• combine two or more DNA molecules to create useful proteins.
• combine useful proteins to create recombinant DNA.