Let's say Nine countries agreed to a treaty requiring each of them to perform a specified action on a certain fixed date, with the actions each conditional on ongoing action taken by other countries. Each country was also to notify the other eight countries it had completed its action.

Are my thoughts right about why these answer choices are wrong??

B) one of the participating parties might not be required to make any changes to take any steps in order to comply with the treaty, but the rest of the paries are required.

Okay let's say country one does not need to act if two does the job. Let's stop here. Is acting or changing the same in ETS's mind. Clearly, the language determines the difficulty of the question. They do not have to make changes because the rest of the parties might be doing their job?

D) This is alittle bit more slick on their part. The agreement specify that the signal for one of the parties for one of the countries to initiate action was when they were notified by the other parties that they had completed their job. Again, is change here the same as action in ETS's mind? That's what aggravates me about this test is what are they thinking?

So country one was dependent on what other parties were doing at the same time. So can one act immediately after two does their job?

I think thats what everybody struggles with. Is my thinking right necssarily, and on test day there is really no way to tell?

Several countries signed a treaty binding each of them to perform specified actions on a certain fixed date, with the actions of each conditional on simultaneous action taken by the other countries. Each country was also to notify the six other countries when it had completed its action.