Party Y political strategists aimed to preach to the middle-voters that Party X domestic policies do not represent their priorities with respect to domestic policy in an attempt to discourage them from voting for Party X and to vote their own Party Y in return.

Now we want to find the answer choice that will best render Party Y political strategies plans unsuccessful.

Option A - Correct
Voters who support Party X are well-informed about the impacts and implications of the Party's domestic and international policies.

Still, they choose to support them over Party Y. As a matter of fact, Party Y tends toward being fruitless in convincing these people to vote them over Party X. Therefore, this answer choice strengthens the argument of rendering Party Y political strategists plan ineffectual.

Option B - Incorrect
We cannot be so sure to say the voters had little knowledge of Party X domestic policies because the passage never emphasized it. They choose to support them literally means they are well knowledgable about their policy. So, this claim is invalid.

Option C - Incorrect
This has nothing to do with the passage at hand. This is irrelevant and wrong.

Option D - Incorrect
This claim is outside the scope of this argument.

Option E - Incorrect
It wasn't stated anywhere that the passage denied Party X of not having any domestic policy. While this statement is true about voters in general, it is wrong with respect to what the argument of this passage is about.

Identify the question
The question is asking us what would weaken the success of political strategist's plan

Deconstruct the argument
PS: doms poli of PT X contrad. w/ MS voters BUT vote PT X b/c fogn poli
PT Y prove PT X doesn't rep their doms poli => win MS voters back

state the goal
The political strategist suggests that Party Y can win back the middle-class voters who support Party X by proving to those voters that Party X does not represent their interest in domestic policy, believing that some middle-class voters support Party X purely due to the party’s appeals about foreign policy. I need to find the answer that makes the political strategist's plan likely to fail.

from right to wrong
A. Many in the middle class who support Party X for its foreign policies also support its domestic policies and are fully aware of the implications of those policies.
=> this attacks the premise of what the political strategist believe, thus weakening the argument
B. Most middle-class supporters of Party X care about foreign policy and know very little about its domestic policies.
=> direct contradiction, if this is true, then the political strategist's plan is likely to succeed
C. Long-term domestic policy sometimes conflicts with short-term domestic policy.
=> out of scope and irreverent to the passage
D. There are topics on which Party X and Party Y have a significant agreement.
=> irrelevant, makes no impact
E. Some middle-class voters are concerned about both domestic and foreign policy.
=>irrelevant distinction, we don't need the distinctions among the middle-class voters