Craig Venter's Team Determined Essential Genes in Bacteria by

Craig Venter's team determined essential genes in bacteria by

A) knocking genes out with transposons; if bacteria survived despite the gene being knocked out, then the gene was an essential gene.
B) adding genes one by one to a bacterium without genes and seeing when the bacterium could survive.
C) knocking genes out with X rays; if bacteria survived despite the gene being knocked out, then the gene was an essential gene.
D) knocking genes out with X rays; if bacteria could not survive despite the gene being knocked out, then the gene was an essential gene.
E) knocking genes out with transposons; if bacteria could not survive when the gene was knocked out, then the gene was an essential gene.