Perkins: According to an article I read, the woolly mammoth's extinction in North America coincided with a migration of humans onto the continent 12,000 years ago, and stone spearheads from this period indicate that these people were hunters. But the author's contention that being hunted by humans contributed to the woolly mammoth's extinction is surely wrong since, as paleontologists know, no spearheads have ever been found among the many mammoth bones that have been unearthed.

Which of the following, if true, provides the strongest reason for discounting the evidence Perkins cites in arguing against the contention that being hunted by humans contributed to the North American extinction of woolly mammoths?

• AAt sites where mammoth bones dating from 12,000 years ago have been unearthed, bones of other mammals have rarely been found.
• BThe stone from which stone spearheads were made is unlikely to have disintegrated over the course of 12,000 years.
• CConditions in North America 12,000 years ago were such that humans could not have survived there on a diet that did not include substantial amounts of meat.
• DCave paintings in North America that date from 12,000 years ago depict woolly mammoths as well as a variety of other animals, including deer and buffalo.
• EBecause of the great effort that would have been required to produce each stone spearhead, hunters would have been to leave them behind.