This is a Strengthen question.
We should find the Prem/Conc of the argument and then consider any objections/assumptions that come to mind.
Conclusion:
University education should emphasize liberal arts rather than technical training.
(why?)
Premise:
[because] the reasoning skills you get from liberal arts allow you to adapt to new challenges and handle jobs you haven't even been trained to do.
Counterpoints:
The primary purpose of university education is making students employable
+
Technical training prepares students for a particular sort of job.
What are the gaps/weaknesses/assumptions/potential objections?
How does liberal arts better satisfy the primary goal of making students employable than technical training does?
How would we play devil's advocate and argue that university education should emphasize technical training instead of liberal arts?
We might argue that a graduate will be more employable being narrowly trained for one type of job than he would be if he only had the reasoning skills to potentially take on any number of jobs.
We might argue that most jobs in the job market require the type of specialized training you only get from technical training.
We might argue that students can get the reasoning skills that a liberal arts education provides elsewhere, so we don't need to make liberal arts the focus of university education.
These three objections would weaken the argument. However, on a Strengthen question, we often see the correct answer ruling out one of our objections, so it still pays to think through them.
(E) is the correct answer because it rules out a potential objection. If technical training DID help students acquire reasoning skills, then liberal arts ed. would have no advantage over technical training (thus, weakening the author's argument). The author was assuming that a student WOULDN'T get reasoning skills if we emphasized technical training. Thus, this answer strengthens by providing us with one of the author's assumptions / ruling out a potential objection.
=== other answers ===
(A) This doesn't strengthen. The author accepts that the primary purpose of college is to make students employable. He's making the case that a liberal arts education would better prepare students for a variety of employment opportunities/challenges. The normative modifiers of "good" education and "good" jobs are out of scope.
(B) This weakens the argument. The author wants us to think that the highly specialized technically trained graduates are not as employable as the unspecialized liberal arts graduates.
(C) The issue of which is more "interesting" is out of scope. The author isn't trying to prove that a liberal arts education leads to a more interesting life than a technical training education would.
(D) This answer feels like it's saying, "liberal arts stuff is more important than technical training stuff". However, "Having a general understanding of life" is way too much of a language shift from "the reasoning skills to adapt to new intellectual challenges". We don't know from the argument that liberal arts provides you with a better general understanding of life than technical training would.