Extract some valueable information:

(+ is pro, - is contra)
+ 2nd sentence: WE NEED A THIRD PARTY! (main point)
=> opposite main point (we do not need a third party)
- Some(opposite).. Americas success stems from 2 party system ...blabla (paraphrase the opposite opinion).. supports the opposite main point
+ opposite the opposite(YET)... Most European countries have multi-party systems (and work).

(A) main, premise CROSS OFF
(B) oppose premises, claim information about euro systems is not a claim CROSS OFF
(C) support opponent main, premise against that support
(D) opponents primary claim, evidence proposed in opposition to the first
(E) claim by opponents, claim second is not a claim CROSS OFF

So we are left with (C) and (D).

IMO (C) should be right, the first section is not the opposite claim. Furthermore, the second section compares european countries to America. This comparison seems to be not good enough to be called an evidence.
The first section supports the opponents main point, the second section is kind of a premise (although I do not like to call this comparison a premise (could someone explain that to me?)).

Please correct my analysis if you find a mistake.

mowie wrote:Extract some valueable information:

(+ is pro, - is contra)
+ 2nd sentence: WE NEED A THIRD PARTY! (main point)
=> opposite main point (we do not need a third party)
- Some(opposite).. Americas success stems from 2 party system ...blabla (paraphrase the opposite opinion).. supports the opposite main point
+ opposite the opposite(YET)... Most European countries have multi-party systems (and work).

(A) main, premise CROSS OFF
(B) oppose premises, claim information about euro systems is not a claim CROSS OFF
(C) support opponent main, premise against that support
(D) opponents primary claim, evidence proposed in opposition to the first
(E) claim by opponents, claim second is not a claim CROSS OFF

So we are left with (C) and (D).

IMO (C) should be right, the first section is not the opposite claim. Furthermore, the second section compares european countries to America. This comparison seems to be not good enough to be called an evidence.
The first section supports the opponents main point, the second section is kind of a premise (although I do not like to call this comparison a premise (could someone explain that to me?)).

Please correct my analysis if you find a mistake.

I gues I am more toward D. I think the first part of BF is an assertion (not a support) made by a person who takes the opposite position against the main point of the argument. What would be the OA???

I also left C and D.
I would go with D because I think that the 2nd boldface is not a premise but an evidence.

OA please

IMO (C) should be right, the first section is not the opposite claim. Furthermore, the second section compares european countries to America. This comparison seems to be not good enough to be called an evidence.
The first section supports the opponents main point, the second section is kind of a premise (although I do not like to call this comparison a premise (could someone explain that to me?)).

Firstly why a comparison cant be a premise?:)

it can be a premise.

But here it is an evidence provided to oppose the first point.

one more for D.

This argument presents a claim that America needs a permanent third party. This claim is the argument's conclusion, in fact. The author then cites the view held by critics of this claim and notes their subordinate assertions that a third party would slow the legislative process and impede governance. Finally, the author cites European countries to contradict the opponents’ claim and their evidence.

(A) This choice is incorrect because the first boldface is not the main point of the argument. It is the conclusion of the argument’s opponents. Furthermore, the second boldface is a premise that supports the actual conclusion, not the claim made by the opponents.

(B) This choice is incorrect because the first boldface does not oppose the premises of the argument; it opposes the conclusion. Furthermore, the second boldface is a premise that supports the conclusion; it is not the conclusion.

(C) This choice is incorrect because the first boldface is the actual position held by the opponents, not a premise for their position. This choice does correctly state that the second boldface is a premise that argues against the position held by the opponents.

(D) CORRECT. The first is the claim of the argument’s opponents, and the second is evidence that contradicts the opponents’ claim.

(E) This choice is incorrect because the second is not the claim that the opponents are opposing by asserting the first boldface. They assert the first boldface to oppose the conclusion of the argument.

I am pretty sure that the right answer is D.