一道OG诊断测试部分的CR题，没有搜到旧帖，大概比较容易吧- -|||  如下：

21. Metal rings recently excavated from seventh-century settlements in the western part of Mexico were made using the same metallurgical techniques as those used by Ecuadorian artisans before and during that period. These techniques are sufficiently complex to make their independent development in both areas unlikely. Since the people of these two areas were in cultural contact, archaeologists hypothesize that the metallurgical techniques used to make the rings found in Mexico were learned by Mexican artisans from Ecuadorian counterparts.


Which of the following would it be most useful to establish in order to evaluate the archaeologists’ hypothesis?


(A) Whether metal objects were traded from Ecuador to western Mexico during the seventh century
(C) Whether artisans from western Mexico could have learned complex metallurgical techniques from their Ecuadorian counterparts without actually leaving western Mexico


答案是A，我选的C...看了解释后大致明白了为什么是A，但是对C又说不出理由来。。而且OG的解释是认为有了metal objects的贸易后就可能把技术也传过去，那为什么不能认为像C项那样，是有厄瓜多尔的同行直接过来教了呢。。该怎么排除C项？

顺带附上OG的解释，还请达人解答！谢谢！
Argument Evaluation
Situation Metal rings excavated from seventh-century settlements in western Mexico were made with the same complex techniques used in Ecuador before and during a period when the two cultures were known to be in contact. Mexican artisans are thought to have learned the techniques from Ecuadorian artisans.
Reasoning What point could best be applied in evaluating this hypothesis? Consider what specific information would help to assess the archaeologists’ theory. It is given that the two areas had some cultural contact. If it were determined that metal objects were traded from one culture to the other, it could be possible that the metalworking techniques were passed along as well. Such evidence would be relevant to the hypothesis that Mexican artisans saw the work of their Ecuadorian counterparts and, from this exchange, learned the techniques to make the metal rings.
A Correct. Th is statement properly identifies information that would be useful in the evaluation of the archaeologists’ hypothesis.
C The hypothesis is not about where Mexican artisans learned the techniques, but whether they learned them from the Ecuadorians.
The correct answer is A.

LZ可能意思理解错了~C主要讨论的是墨西哥的人是不是离开西墨西哥去学习技术的。但是文章的结论是这个技术是墨西哥人从厄瓜多尔人那学来的。也就是文章并没有讨论时在哪里学的，只是问谁学的问题。显然，A说这个东西是不是在那段时间从厄瓜多尔传来，如果是，文章被加强，不是，文章结论被削弱。至于C，不论是否，都和文章的结论不相关！你在哪里学不影响你向谁学的，你要高兴，一起来中国学也可以~呵呵！