"E. coli can be considered a manufacturing unit in the field of genetic engineering."
Explain this statement.

A. The recombinant DNA produced by the combination of an E. coli DNA and the gene of interest are inside the donor organism’s body, where it is multiplied and expressed into its protein product.

B. The recombinant DNA produced by the combination of a vector and the gene of interest are inserted in the E. coli, which produces multiple copies of this recombinant DNA along with the chromosomal DNA and expresses the gene.

C. The recombinant DNA produced by the combination of E. coli DNA and the DNA of the donor organism are inserted inside the E. coli, where it will be expressed into its product.