太奇怪了！请教一道LSAT逻辑

znprc

题目是：
Either Perry’s faction or Tucker’s faction, but not both, will win control of the government. If Perry’s faction wins, the nation will suffer economically. If Tucker’s faction wins, the nation will suffer militarily.

Given the statements in the passage, which one of the following statements must be true?

（A) It is possible, but not certain, that the nation will neither suffer economically nor suffer militarily.

(B) If the nation suffers economically, it is certain that Perry’s faction has won control of the government.

(C) It is certain that the nation will suffer either economically or militarily, and also certain that it will not suffer both.

(D) If the nation suffers militarily, it is possible, but not certain, that Tucker’s faction has won control of the government.

(E) If the nation suffers both economically and militarily, it is certain that neither Perry’s faction nor Tucker’s has won control of the government.


答案是D。但我认为B和C才对，不是吗？

dandan74

这道题考得是逆命题。也就是，原命题正确，它的逆命题不一定正确。
D正好是说的这一点。
B说原命题的逆命题一定正确，是不对的。
C偷换了原题的概念，不论Perry's 还是Tucker's 取得control，都不能说明这个国家只能suffer一个结果。" it will suffer both" is still possible.
E和C错在了同样的点上。

znprc

谢谢