CR:Rabbits were introduced to Numa Island in the

[Khush]

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.

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.

I marked the correct answer C by elimination, but i am not getting the logic behind the answer choice.

As per my understanding, the evidence in the passage says that on implementation of the plan, the virus MAY infect the bilby. However, the conclusion says that "the plan will SURELY increase the threat to bilby". so, it seems as if the flaw in reasoning is that "certainty" is same as "chance". But does choice C address this flaw?

I think choice C says that there is already an increased threat to bilby by rabbits. i.e. the effect (endangered bilbies) is there whereas the cause (the use virus as per the plan of the government) is absent, weakening the argument.
Am i thinking in the right direction?

[NL]

i am not getting the logic behind the answer choice.

I think the main reasoning is: the government’s plan of "using a virus" will increase the threat to native wildlife".
C says: NO, the criminal is rabbits!

(it's cause-effect case, if you want to categorize it)

[RonPurewal]

If choice C is true, then killing the rabbits will help the bilbies, by leaving more food for them.