Most archaeologists have held that people first reached the Americas less than 20,000 years ago by crossing a land bridge into North America. But recent discoveries of human shelters in South America dating from 32,000 years ago have led researchers to speculate that people arrived in South America first, after voyaging across the Pacific, and then spread northward.

Which of the following, if it were discovered, would be pertinent evidence against the speculation above?

(A) A rock shelter near Pittsburgh, Pennsylvania, contains evidence of use by human beings 19,000 years ago.

(B) Some North American sites of human habitation predate any sites found in South America.

(C) The climate is warmer at the 32,000-year-old south American site than at the oldest known North American site.

(D) The site in South America that was occupied 32,000 years ago was continuously occupied until 6,000 years ago.（B）

(E) The last Ice Age, between 11,500 and 20,000 years ago, considerably lowered worldwide sea levels.

我觉得这里B存在纰漏呀，如果B成立那么people first reached the Americas less than 20,000 years ago by crossing a land bridge into North America.就不对了。B说明北美有人的时间至少要比南非有人的时间，32,000年还要长呀。

我认为“people first reached the Americas less than 20,000 years ago by crossing a land bridge into North America.”已经被后面的发现推翻了。

问题问的是要推翻上面的speculation, 而不是支持Most archaeologists的说法。