以下是gmat逻辑题库中gmat逻辑真题例题分享：
Which of the following most logically completes the argument?
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. Therefore, the planned introduction into that region of ant flies, which prey on Loma ants, would benefit public health, since .
(A) ant flies do not attack black ants other than Loma ants
(B) Loma ants are less effective than many bird species in competing with rodents for seeds
(C) certain other species of black ants are more effective than Loma ants in competing with rodents for seeds
(D) the sting of Loma ants can also be fatal to rodents
(E) some pesticides that could be used to control Loma ants are harmful to the environment
题目类型：
complete the argument
题目翻译：
因为需要与啮齿类动物抢种子，黑蚁可以帮助控制啮齿类动物的繁殖。这是一件好事，因为啮齿类动物是于人类无益的。但是，黑蚁中有一种叫做L的品种最近侵入了一个地区，L有一种刺对人类是致命的。因此，对该地区引入捕食L的蚁蝇对人的健康有好处。
解题思路：
要考虑两方面的因素，一方面，要减少L的数量;另一方面，要有黑蚁控制啮齿类动物的数量。
逐项分析：
A、正确选项。蚁蝇只吃L不吃黑蚁的其他品种，所以L和啮齿类动物的数量都可以得到控制。
B、在与啮齿类动物抢种子这件事情上，L不如鸟类。无关项。
C、在与啮齿类动物抢种子这件事情上，L不如其他各类的黑蚁。无关项。
D、如果这样的话，引入蚁蝇就不一定是件好事了。
E、一些可以控制L的杀虫剂对环境有害。无关项。
正确选项：
A