求助一道逻辑题，高手帮忙～

Determining the authenticity of purported pre-Columbian artifacts is never easy. Carbon-14 dating of these artifacts is often impossible due to contamination by radioactive palladium (which occurs naturally in the soils of Central and South America). However, historians and anthropologists have evolved two reliable criteria, which, utilized in combination, have proven effective for dating these artifacts. First, because authentic pre-Columbian artifacts characteristically occur in a coarse, granular matrix that is shifted by major earthquakes, they often exhibit the unique scratch patterns known as gridding. In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas.

The criteria above would be LEAST useful in judging the authenticity of which of the following?

(A) An ax head of black obsidian, unearthed from a kitchen midden

(B) A pottery bowl with a red ocher design, found in the ruins of a temple

(C) A set of gold ear weights, ornamented with jasper pendants

(D) A black feather cape from a king’s burial vault

(E) A multicolored woven sash found near the gravesite of a slave

答案是D,我选的C。

这道题还是有点不太清楚，好像五个选项的区别不是很明显，请高手指点～thanks in advance!

这个题不晓得怎么用逻辑那套方法去做。但是看了四个选项，只有D里面的羽毛披肩不可能出现原文所述的那两种特点啊，所以那两条标准对于判断D里的东西是不是属于pre-C时代是没有多大关系的。

羽毛披肩不会出现粗糙的、颗粒状的模型；而如果要长期埋在土里的话（根据exposure to the minute amounts of magnesium in the soil of the Americas判断是要埋土里的），肯定早就烂成碎片了。

"In addition, true pre-Columbian artifacts show a darkening in surface color that is caused by centuries of exposure to the minute amounts of magnesium in the soil of the Americas."

(A) An ax head of black obsidian, unearthed from a kitchen midden

(B) A pottery bowl with a red ocher design, found in the ruins of a temple

(C) A set of gold ear weights, ornamented with jasper pendants

(D) A black feather cape from a king’s burial vault

(E) A multicolored woven sash found near the gravesite of a slave

我在想是不是跟颜色有关？两条标准中的第二条提到show a darkening in surface color ...，D中的东西已经是Black的了，无法分辨什么是否darkening...至于A会不会是跟第一条标准有点关系？

感觉这道题纯粹在考阅读啊。。。