PrepTest 152, Section 2, Question 15

What we’re looking for

Working the answers

• A
  Correct

  The same underground deposit also supplied nearby riverbeds. Now there is another way to get gold with the matching composition: collect it from a riverbed rather than dig it out of the mine.

  That is different from my initial concerns about changing ratios or the mine's age. The chemical match can be accurate while the conclusion about extraction from this particular mine is mistaken. A doesn't prove the gold came from the river; it makes that a plausible alternative consistent with the evidence.

• B

  A civilization connected to both the mine and the artifacts could make the proposed origin more plausible. The answer is tentative, so it doesn't establish that connection firmly, but it certainly doesn't give us a reason to doubt the mine supplied the gold. Weakening requires the relevant direction of support, not merely uncertain wording.

• C

  This goes against my timing concern. A mine already operating centuries before the artifacts were made would be available as a source. Its age doesn't establish that it supplied these objects, but it doesn't present the too-late opening that would undermine the claim.

• D

  Recycling an earlier artifact doesn't settle where its gold originally came out of the ground. Imagine an old gold spoon melted down into a new object: the spoon's gold could still have been dug from this mine. The conclusion doesn't require the gold to pass directly from the mine to the particular artifact without an intermediate use.

• E

  Transport over a long distance doesn't identify a different source for the gold. We aren't told the artifacts had to stay near the mine, and moving the gold elsewhere wouldn't undo its origin. E gives a possible journey after extraction without challenging where the extraction occurred.