Geologist: A geological fault in the mountain under which the proposed nuclear waste storage facility would be buried could, after a few thousand years, cause the contents to seep out or water to seep in.
Your task
Find the choice that makes the argument's conclusion more likely to be true.
Common trap
Answers that are consistent with the argument but add no real support, or that strengthen a claim the argument doesn't make.
Winning move
Locate the gap between evidence and conclusion, then pick the choice that closes it.