8. (A)
Question type: Weaken the conclusion
The conclusion of this argument is that pollen analysis can help identify where an ancient relic was (and was moved). The support for this is that pollen clings to surfaces and that it can be traced to a geographical area. However, as (A) suggests, if the pollen were to move away from the "source" location, it would no longer indicate where the relic had been. The fact that (A) states the pollen "often" moves from place to place in this way adds further weight to this answer choice’s power to cast doubt on the argument.
(B) is out of scope. The argument does not suggest that pollen analysis is the best or least complicated method for determining the history of a relic’s movement.
(C) is very tempting. If the pollen from a certain plant can be traced to two locations, how would one know which location is the relevant one? Indeed, this would complicate the analysis of the relic’s movements. However, the technique relies on using pollens that are unique to a certain area - so those pollens that are in multiple places would not be used.
(D) is also tempting. If we actually don’t know much about pollen distribution, is pollen analysis a good indicator of location? However, the argument limits itself to discussing the identification of pollen from plants that "are known" to be from a specific location.
(E) is out of scope. The argument does not suggest that pollen analysis is the best or least quickest method for determining the history of a relic’s movement.