20. Seven 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. The simultaneous-action provision of the treaty leaves open the possibility that (A) the compliance date was subject to postponement, according to the terms of the treaty (B) one of the countries might not be required to make any changes or take any steps in order to comply with the treaty, whereas all the other countries are so required. (C) each country might have a well-founded excuse, based on the provision, for its own lack of compliance (D) the treaty specified that the signal for one of the countries to initiate action was notification by the other countries that they had completed action (E) there was ambiguity with respect to the date after which all actions contemplated in the treaty are to be complete.
A: 协议并没有规定这样的规定：if the action haven't been done on a certain fixed date,then the compliance date was subject to postponement. so A is wrong. 另外：我认为这道题是循环论证的错误。所得结论建立在一个未经证实的假设上，此假设又以该结论互为假设。
