I do not clearly understand why answer choice E is wrong. I thought E also strengthens the argument because it shows that when limitation exists, the result did not happen. The passage basically says that removal of the limitation (or A)resulted a more in-depth and cosmopolitan education that ever before (or B). Wouldn't E strengthen the argument by showing that when A does not happen, B also does not happen?

Thanks Jason. I got it. I really appreciate it.

Thanks Jonathan, I see your point and it definitely makes sense. Does the fact that /A -> /B strenghthen the statement that A caused B though?

I understand you do not teach Powerscore here. But, I just wanted to confirm the concept I mentioned above. Are you saying that answer to my initial question is "Yes"

Thanks for your comments. I am still not clear on this. To strengthen /A -> /B, we can say A -> B. For example, according to "Logical Reasoning Bible" by claiming that A caused B, the author assumes that A is the only cause for B and thereby assume that if A does not happen, B does not happen. By using the same logic, if /A causes /B, wouldn't we also have to assume that if /A does not happen, then /B does not happen, which is "A ->B"