请教一道新东方逻辑补充上一道题！Section 6-20

Section 6 第20题

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.

答案是C。这道题的推理过程是怎样的呢？请高手指点下～

本题意思很明确：

七国条约限定成员国在某个届定日期共同行动——如果其他六国都遵从了共同行动条款，那么第七国亦应遵守之。并且，在行动完成后，需通知其他六国。

问题是：这个条约有哪些漏洞？

很明显，漏洞就是，如果七个国家之一未遵从该条约，那么其他六国亦可不遵从。也就是lack of compliance.