一道逻辑老题， 可以帮忙理一下逻辑思路吗？

sillypotato

Archaeologists in Michigan have excavated a Native American camp near Dumaw Creek. Radiocarbon dating of animal bones found at the site indicates that the camp dates from some time between 1605 and 1755. However, the camp probably dates to no later than 1630, since no European trade goods were found at the site, and European traders were active in the region from the 1620's onward.

Which of the following, if true, most strengthens the argument?

(A) Due to trade among Native Americans, some European trade goods would have reached the area before the European traders themselves did.
(B) At all camps in the region that have been reliably dated to the late 1620's, remains of European trade goods have been found.
(C) The first European trade goods to reach the area would have been considered especially valuable and preserved as much as possible from loss or destruction.
(D) The first European traders in the area followed soon after the first European explorers.
(E) The site is that of a temporary camp that would have been used seasonally for a few years and then abandoned.

vincentchang83

感觉这道题不怪怪的：

题干： 欧洲商队从1620年代开始在该地区进行贸易 ==》》 因为这个遗址没有发现欧洲商品的迹象 ==》》 这个遗址应该在1630年以前存在的。

A: 即使没有欧洲商队， 一些欧洲货品在1920年代之前就通过其他途径来到了这一地区。   --- 通过这个条件， 应该判定， 这个遗址存在的年代应该比1920s更早。

B： 所有1620年代后期的camp里面都发现了欧洲商品。  --- 这个应该是能证明那个camp是early 1620s 的吧。

C， D， E 感觉根本无关。。。

leoliangliang

假设：1 European traders left goods at the site
          2 在这个native camp里没有European goods
结论：这个camp是在European traders到来之前留下的。
GAP:European traders 与 goods 是否一定有关。
B选项增强了这种相关性

FlyingC2

最近看了新东方那个的网络课堂。
按他们的分类，这是一道果因的题目。
果因题目问加强，正确答案：没有这个原因，就没有这个结果。

针对这道题：
结果是：这个遗址应该在1630年以前存在的。
原因是：因为这个遗址没有发现欧洲商品的迹象
推测答案：如果这个遗址确实发现欧洲商品的迹象，那么这个遗址很可能是在1630之后存在的。

选项B：所有1620年代后期的camp里面都发现了欧洲商品。