One year ago, a municipality banned dishwasher detergents containing phosphates. Anecdotal evidence indicates that ma...

SamA September 17, 2019

Hello @Minerva,

Let's take a closer look at the last sentence:

Premise: Phosphate pollution from the municipal wastewater treatment plant decreased significantly in the last year.

Conclusion: Some residents did switch to phosphate-free detergent.

D is incorrect, because the percentage of total phosphate pollution that comes from the treatment plant is irrelevant. The author is only looking at one factor to draw the conclusion: the amount of phosphate pollution from the plant this year as compared to last year.

tomgbean November 30, 2019

But if there are waste water from some of the residents being treated at other plants, wouldn't that weaken the author's argument?