This question was discussed before: projectile-weaken-question-79276.html#p596068

5. Archaeologist: A skeleton of a North American
mastodon that became extinct at the peak of the
Ice Age was recently discovered. It contains a
human-made projectile dissimilar to any found
in that part of Eurasia closest to North America.
Thus, since Eurasians did not settle in North
America until shortly before the peak of the Ice
Age, the first Eurasian settlers in North America
probably came from a more distant part of
Eurasia.
Which one of the following, if true, most seriously
weakens the archaeologist’s argument?
(A) The projectile found in the mastodon does not
resemble any that were used in Eurasia before
or during the Ice Age.
(B) The people who occupied the Eurasian area
closest to North America remained nomadic
throughout the Ice Age.
(C) The skeleton of a bear from the same place and
time as the mastodon skeleton contains a
similar projectile.
(D) Other North American artifacts from the peak of
the Ice Age are similar to ones from the same
time found in more distant parts of Eurasia.
(E) Climatic conditions in North America just
before the Ice Age were more conducive to
human habitation than were those in the part
of Eurasia closest to North America at that
time.



Anyway, I thought just reading the argument was confusing. I didn't really understand what the heck was being asserted in the first place.