Thank you so much, Dan! Your explanations really help my understanding of the questions. I didn’t realize that it may be easier sometimes to simply eliminate answer choices as you did for #8, based on the mere fact that “will work” was never truly confirmed in the stimulus, etc. It makes it clear that the point of the argument was never to prove that the backup system would work or not. #16 is also very clear now; simply taking the points and correlating/negating makes it so much easier. I think a lot of times, I try to read the answer choices before working out the question for myself, and it ends up confusing me.
While I’m at it, #17 in this same Prep Test seems similar to #16, but it would really help if you could provide a simplified explanation.