Some of the E. coli bacteria that were originally isolated from a contaminated salad were tetracycline resistant while the others were susceptible. However, when tetracycline-resistant and -susceptible strains were grown together, all of them became tetracycline resistant. This efficient transfer of resistance depends on which of the following?
Cell lysis and the release of DNA from donor bacteria Competent cells Conjugative plasmids Recombinase enzymes