To best isolate mutant bacteria that are alanine auxotrophs from a larger population, What should be done?
1) Inoculate alanine-rich media and observe for any colonies that form
2) Inoculate alanine-poor media and observe for any colonies that form
3) Inoculate a mixture of alanine-rich and alanine-poor media and observe for any colonies that form
4) Inoculate a mixture of alanine-rich and alanine-poor media and observe for any colonies that do not form