This asks to weaken the geologist's argument. I cannot wrap my head around why D is the correct answer. Someone please help!
https://7sage.com/lsat_explanations/lsat-74-section-1-question-23/
... answer choices describe what the argument did (something wrong)/didn't ... do to make a valid argument)
- It really helps if ... with the ones in the argument.
Jon's conditional breakdown shows an example of how the answer choice has to be sufficient based on the argument...
https://7sage.com/lsat_explanations/lsat-55-section-1-question-12/