I chose E for this one, because I began to pay attention to qualifiers. I have spotted that "tourists trample most of the small shrubs that are necessary to the survival of any monarch butterflies that fall off the trees." Since if the monarch butterflies don't fall off the trees, then the tourists did not endanger them at all after all, undermining the author's argument.
I thought E would have the strength to either weaken or strengthen the stimulus, depending on its validity.
Can someone help me understand how B is a better answer than E?
Should I look at the stimulus as a whole rather than just the
P-->C relationship? Is that why I got it wrong?
Thanks for your help.