I would say (E).

I negotiations may begin but are not guaranteed to result in agreement. The argument is just talking about begining negotiations. The agreement comes later.

Nested Logic. Fun!. This is a tough question.

A.

Makes a definitive statement that the ceasefire has not been violated by either country. Perhaps they violated the cease fire in the past, but have been quiet so that they can engage in negotiations. Specific ceasefire is not called out. Right now they have not violated cease fire doesnt imply that they have never violated ceasefire.

E makes the point that the agreement is dependent on other countries exerting pressure, which is true whether the agreement is reached or not and even if we are in the early stages of negotiation and is explicitly stated in the stem. The fact that for the agreement to be reached, countries have to exert pressure and continue exerting it is true at the time the question is refering to...

A.

Unless negotiations begin soon, the cease-fire will be violated by one of the two sides to the dispute.

No negotiations => Cease-fire violation. X => Y scenario.

X => Y does not mean (Not X) => (Not Y).
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Anyone who has never made a mistake has never tried anything new. -Albert Einstein.

yes A seems to be the best answere.

wht's the OA?

Cease fire will be broken unless negotiation begin soon. (Cease fire will stop if no negotiation. ) A (ceasefire)=>B(negotiation) Negotiation is necessary condition of cease fire.
Negotiation will begin only if other countries pressure. B(negotiation)=>C(other country) Other country is necessary condition for negotiation.
Negotiation will begin only if international troops can counter agreesion from both side. B (negotiation)=>D (international troops) Troops is necessary condition for negotiation.
Agreement only if other countries continue to pressure. E (agreement)=>C (other country)

Negotiation begins. (B)

(A) The cease-fire has not been violated by either of the two sides.
No. A=>B but not necessarily B=>A. If there's no negotiation, then cease fire will be broken. If there is negotiation, there may or may not be cease fire.

(I think in the sticky my explanation about "unless" is wrong. I will correct it upon further examination.)

(B) International troops enforcing the cease-fire have demonstrated that they can counter aggression from either of the two sides.
Yes B=>D

(C) A major incentive for the two sides to resume hostilities has been suppressed.
Yes B=>D'

(D) Other countries have exerted pressure on the two sides to the dispute.
Yes B=>C

(E) The negotiations’ reaching an agreement depends in part on the actions of other countries.
Yes. C is the necessary condition for E.

(A) The cease-fire has not been violated by either of the two sides.
- True. Prescence of international troops must enforce cease-fire before negotiations can start

(B) International troops enforcing the cease-fire have demonstrated that they can counter aggression from either of the two sides.
- True. Stated in passage.

(C) A major incentive for the two sides to resume hostilities has been suppressed.
- True. International troops enforcing the cease-fire has to be able to suppress the incentive for the two sides to resume hostilities

(D) Other countries have exerted pressure on the two sides to the dispute.
- True.

(E) The negotiations’ reaching an agreement depends in part on the actions of other countries.
- This is the answer. In the passage, we're told 2 conditions for negotations to take place:
1) Countries pressuring them to the negotiation table
2) International troops demonstrating their capability to suppress agression from both sides
Choice E states that negotiations' reaching an agreement depends in part on actions of other countries. But from passage, we know it depends wholly on action of other countries.

E it is.

Honghu,

This part of your sentence is contradictory.
'The agreement depends on the pressure from other countries, as well as some other things'
The 'other things' you mentioned are continuous pressure from other countries. International troops are also provided by other countries. None of the 'other things' mentioned in fact are from the 2 countries in dispute. As such, I find E more appealing

(E) The negotiations’ reaching an agreement depends in part on the actions of other countries <-- the actions here are the pressure to beging negotiation, continuous pressure to reach agreeement, and international troop prescence to ensrue negotiation can start first of all. From the looks of it, the outcome is wholly dependent on other countries' contribution.

The point is, other countries are a necessary condition. In other words, without the other countries, there won't be an agreement. However, other countries is not a sufficient condition. Even if the other countries continue to pressure, and the the troops are there, and so on, it is still possible that an agreement is not reached. Maybe one of the leaders on one side suddenly dies and the whole thing falls apart. Who knows. The point is, the stem says an agreement will not be reached without other countries' pressures. But it didn't say if other countries keep pressing we will be able to get an agreement for sure.

Actually trying to explain my point has cleared my thought as well. (Let me discovered a mistake of myself too. ) Thanks for the great discussions!