In 2010, Scientists Developed a Series of Overlapping Oligonucleotides That

In 2010, scientists developed a series of overlapping oligonucleotides that extended a full 1.08 million base pairs and used it to develop the first complete organism using a synthetic genome. The newly created cells had normal growth and morphology. In addition to the synthetic genome, why did the investigators also include a gene that confers resistance to tetracycline?

A) By including an exogenous gene, they could confirm propagation of the genome by PCR.
B) The tetracycline resistance gene increases the genomic stability of genomes in prokaryotes.
C) The tetracycline resistance gene destabilizes the genome of the host DNA allowing the novel synthetic genome to survive.
D) The tetracycline resistance gene allows the selection of only the cells that are resistant to tetracycline and thus cells that survive selection carry the novel synthetic genome.