Rabbits were introduced to Numa Island in the nineteenth century. Overgrazing by the enormous population of rabbits now menaces the island’s agriculture. The government proposes to reduce the population by using a virus that has caused devastating epidemics in rabbit populations elsewhere. There is, however, a chance that the virus will infect the bilby, an endangered native marsupial. The government’s plan, therefore, may serve the interests of agriculture but will clearly increase the threat to native wildlife.（weaken“对argriculture有益，对wildl威胁”为什么是C——C不是support了吗？）
Which of the following, if true, most seriously weakens the argument?
A. There is less chance that the virus will infect domestic animals on Numa than that it will infect bilbies.
B. There are no species of animals on the island that prey on the rabbits.
C. Overgrazing by rabbits endangers many of the plants on which bilbies feed.
D. The virus that the government proposes to use has been successfully used elsewhere to control populations of rabbits.
E. There is no alternative means of reducing the rabbit population that would involve no threat to the bilby.
我也看到有人说A对的A说 the chance( that virus infect domestic animals on Numa )is less than the chance (that the virus infect bilbies)
也就说： 伤害到bilbies(native animals)的几率比伤害到家养动物（指代了本地农业）的大。
A分两部分来看：
1、当真的伤害到bilbies时，也就应了结论（一部分）：government plan increase the threat to native animals，这时，就是加强结论，而绝不是削弱了。同时，virus法还灭了兔子，which 危害到了本地农业，这更加说明了加强。
2、当没伤到bilbies时，我不用多言了，这还是加强了结论。
