I eliminated D because it says "unless we are assured that.....". I still don't see anything in the stimulus that mentions the extent to which we "are assured" of anything. I would've liked D a lot better had it said "We should not allow a change to occur unless the change will not jeopardize anything that is important to us". I selected A and I see why it's incorrect, but I am struggling to see how the language of "we are assured that" doesn't ruin D.

Is the reason why D is incorrect because we don't know how many of Mary Cassatt's works are unknown relative to the number of her known works?

@LowriThomas Thank you for clarifying why this conditional is not intuitive. I was having a difficult time with D precisely because I saw "only" and immediately thought the pure free market economy was the necessary condition (I mistakenly ignored the "assured"). I have seen accomplished tutors on other platforms get this one wrong.

My proctor also interrupted me several times.....it was beyond frustrating. The first one was during the first RC passage, and they interrupted to tell me to reposition my camera. I filed a complaint and am seeking to re-test in person. I had no idea the proctors would be that annoying! Anyways, I feel your frustration.