By competing with rodents for seeds, black ants help control rodent populations that pose a public health risk. However, a very aggressive species of black ant, the Loma ant, which has recently invaded a certain region, has a venomous sting that is often fatal to humans. Ttherefore, the planned introduction into that region of ant flies, which prey on Loma ants, would benefit public health. Which of the following, if true, most strengthens the argument? ['Certain other species of black ants are more effective than Loma ants in competing with rodents for seeds.', 'The sting of Loma ants can also be fatal to rodents.', 'Ant flies do not attack black ants other than Loma ants.', 'The use of pesticides to control Loma ants could have harmful effects on the environment.']