Thanks for the question! Yeah, so (D) is definitely a tricky answer choice here. But remember what the stimulus is telling us here: there’s this study that tells us that many consumers who were buying bottled water were getting water that was less safe than what they could get much more cheaply at the public water supply. And the study had a lot of publicity, but sales of bottled water continued to rise.
So the heart of the paradox here is the fact that there’s this cheaper, safer source of water, but bottled water sales are still increasing. We need an answer choice that would explain why bottled water sales are still increasing to resolve this paradox. (D) tells us that the rate of increase in the sales of bottled water has slowed down since the government study was published. Sure, it’s totally possible that the rate of sales increase could’ve slowed and sales themselves could’ve risen (throwback to calculus). But that doesn’t explain anything about why the sales of bottled water are still increasing. We would expect sales of water bottles to decrease. Knowing that they’re increasing at a slower rate doesn’t tell us why they’re still increasing. Why are people still getting bottled water at all, when they could be getting this cheaper, safer water from the public supply, and they (presumably) know about the results of the study? (D) just doesn’t resolve the paradox nearly as well as (C) does. For that reason, (D) is wrong.
Hope this helps! Feel free to ask any other questions that you might have.
