PT47 S1 Q22

babybenny

I tried to understand why C is an answer and B is wrong. But I still don't find out why.
I know the conclusion of the stimulus is this practice greatly increases the health risk~part.

When I looked C only, it made me think it attacked "this practice" part, not greatly increases the health risk to U.S consumers.
But for weaken and strengthen questions, we should attack/strengthen a "conclusion" as far as I know.
So I thought I should attack this practice greatly increases the health risk to U.S consumers which is the conclusion and tried to find out another possibility or sth (e.g "NOT increases the health risk to US consumer") even if
what the premises said. So that's why I chose B.
So I'm really confused how C is an answer, but B cannot be. Why C should be an answer and B is not?

And I really wonder how I can distinguish between which case I should attack the whole conclusion and attack just some/another part of the conclusion (just like "this practice" part in this question) when I encounter weaken/strengthen questions which means we should attack/strengthen a conclusion.
As far as I remember, I saw some of the weaken/strengthen questions that I shouldn't attack/strengthen the whole part of the conclusions just like this one.

Can anyone explain me?
Thanks!

nye8870

This is what I see: ac-B offers information that most of the US exported pesticides are actually not the banned ones (in the US). Ok...but that means we still export some banned ones and the conclusion follows that that practice puts US at risk. So it doesn't really weaken the conclusion. Now ac-C basically say the countries from which we get our produce (which has been tainted with the banned pesticides) are getting it from other countries as well as the US. I think it weakens because now that we know that those other countries will still be putting it on their produce for export, whether we export banned pesticides or not, it is still coming in. So the risk is still there no matter whether we stop exporting them or not.