Herbalist: While standard antibiotics typically have just one active ingredient, herbal antibacterial remedies typically contain several. Thus, such herbal remedies are more likely to retain their effectiveness against new, resistant strains of bacteria than are standard antibiotics. For a strain of bacteria, the difficulty of developing resistance to an herbal antibacterial remedy is like a cook' s difficulty in trying to prepare a single meal that will please all of several dozen guests, a task far more difficult than preparing one meal that will please a single guest. In the analogy drawn in the argument above, which one of the following corresponds to a standard antibiotic? ['several dozen guests', 'a cook', 'a single guest', 'the ingredients available to a cook']