@nye887085 Thanks nye8870! But I still think D is unnecessary. If there is ONE (or more) student who are "least enthusiastic" and "not most committed", then the course fails to serve its purpose. Thus, it is not necessary to say that "All the least enthusiastic are not most committed". That's D. Could you correct me if I am wrong? @jidazhengqian344 Could you take a look at our discussion?

Yes I really agree with you! I think it is sufficient but not necessary ! Could anyone explain it?

Hi J,Y, thanks for the explanation. I want to challenge D. If we negate it, then "there is an additional explanation", for example, the campus is not safe. Then, "if we want to increase the applicant pool",then the conclusion can be "we need to both increase safety and tuition".But the conclusion can also be" we need to increase safety, then we may not need to raise tuition". I think in this way the conclusion is weakened. Could you tell me where I am wrong? Thank you.

It is not "wrong=not right", but "wrong→not right". From the stimulus we can be sure that "It is wrong to restrict publications that are only restrictive." Suppose there are three status: "wrong, neutral, right". Then "not right"= wrong+neutral. Thus we can be certain that "if wrong, then it is not right".