The scientists concluded that either antibiotic A or antibiotic B should be prescribed to patients with food poisoning. Why should antibiotic A or antibiotic B be prescribed?

In this experiment, the effectiveness of an antibiotic is indicated by the size of the zone of inhibition – the clear circular area around the paper disc where bacteria have been killed and cannot grow. By observing Figure 4, we can see that antibiotics A and B have produced the largest zones of inhibition compared to C, D, and E. This means they were the most effective at killing this particular strain of Salmonella bacteria, and therefore would be the best choice for treatment.