The naked mole rat is a pest to the farmers of Pellaville. The farmers

Premise : The naked mole rat is a pest to the farmers of Pellaville. The farmers plan to reduce the rat population by poisoning the stream out of which the mole rats drink.

Ques : Which of the following, if true, is the best support for the scheme of the farmers?

Pre-thinking : Wew need find the option which supports the farmer scheme that which supports the fact that by poisoning the stream out of which mole rats drink, rat population will reduce.

Lets analyse the options now :
(A) The poison that will be used in the stream is not toxic to the farmers' livestock - Correct - This looks like a promising option. This mean only rats will be kileed and livestock will not be affected by the poison.

(B) The naked mole rat is not susceptible to most conventional poisons - Incorrect - We need to find an option that strengthens the argument, if this is true for the poison that farmers are using, it will weaken the farmers plan.

(C) The befurred vole, a relative to the naked mole rat, is most effectively controlled with contraception rather than with poison - Incorrect - This is totally irrelavant and not related to the passage in nay way. Irrelevant.

(D) The poison to be used is less expensive than other poisons - Incorrect - We are not concerned about the price of the poison but whther the poison will effective in reducing rats population. Irrelevant.

(E) The poison will be most effective if administered after the harvest - Incorrect - No information has been given that poison was administered before or after the harvet. Hence, the does not affect the farmers plan in any way. If it is administered before the harvest, less rats will be killed and if it is administered after, more rate will be killed.
In either way, rats number will be reduced and farmers will acheive the plan. Not related.

We have to strengthen the farmers plan
(A) The poison that will be used in the stream is not toxic to the farmers' livestock - Correct among other choices
(B) The naked mole rat is not susceptible to most conventional poisons - out of scope
(C) The befurred vole, a relative to the naked mole rat, is most effectively controlled with contraception rather than with poison - weakens
(D) The poison to be used is less expensive than other poisons - out of scope
(E) The poison will be most effective if administered after the harvest - weakens as moles are considered pests to the harvest

The naked mole rat is a pest to the farmers of Pellaville. The farmers plan to reduce the rat population by poisoning the stream out of which the mole rats drink.
Which of the following, if true, is the best support for the scheme of the farmers?

Okay, you would have got the answer as A and that is correct. I am dividing my post in 2 sections. 1-> Approach to solve, 2-> My learnings
Approach
I used POE.
Option B somehow weakens the argument of poisoning.
Option C is providing an alternate solution so in another sense it is weakening the argument.
Option D Does it really matter whether the poison is cheap or expensive. Farmers are trying to kill the naked mole rat.
Option E pests attack before harvesting and not after harvesting.
So it's clear answer is A.

My learnings
On my first read I thought that poison might not be toxic to farmer's livestock, but what if the stream is also used by farmers. They might get impacted.
But no information was given on that in question, so keeping Option A as a contender was the right option. And as I keep going on, the other options didn't even make the contenders list.

(A) The poison that will be used in the stream is not toxic to the farmers' livestock
(B) The naked mole rat is not susceptible to most conventional poisons
(C) The befurred vole, a relative to the naked mole rat, is most effectively controlled with contraception rather than with poison
(D) The poison to be used is less expensive than other poisons
(E) The poison will be most effective if administered after the harvest

The naked mole rat is a pest to the farmers of Pellaville. The farmers plan to reduce the rat population by poisoning the stream out of which the mole rats drink.

Which of the following, if true, is the best support for the scheme of the farmers?

(A) The poison that will be used in the stream is not toxic to the farmers' livestock Strenghthens
(B) The naked mole rat is not susceptible to most conventional poisons For all it's worth, this ones weakens
(C) The befurred vole, a relative to the naked mole rat, is most effectively controlled with contraception rather than with poison befurred vole is OOS
(D) The poison to be used is less expensive than other poisons Cost is OOS
(E) The poison will be most effective if administered after the harvest Time of poisoning is OOS