[Grammar] disagree

[Ashiuhto]

I'm confused by the followng sentence.
Which option in the blank is acceptable?

The two countries have peacefully agreed ____________ about the precise location of their common border.

(1) disagreeing (2) which disagrees
(3) to disagree (4) they disagreed

According to my judgement, I would choose (3) is acceptable. However, I can't figure out its meaning.

 

[Barb_D]

You're right.

When you "agree to disagree" it means that you don't have the same opinion, but you can accept that the other person has a different point of view. You don't have to agree on everything to continue you're discussions or relationship.

In this case, neither country is going to set up an armed outpost to defend where it thinks the border is.