choice (b) is correct: if government efforts in general have been shown to be largely ineffectual, then that trend is likely to continue to hold sway in this particular case.

to take care of one popular objection: you may wonder whether the statement about "government efforts" in general applies to the efforts of the specific government referenced in the passage. especially if you have extensive experience with cr problems in general, you may be loath to connect any specific with any generality.
let's take care of that one:
you should read government efforts as, well, "government efforts".
in other words, government efforts in general - an umbrella that does, indeed, subsume the efforts of the particular government in question.

also, note the definitive nature of the answer choice: ...have been shown to...
this wording indicates that we have sufficient evidence to KNOW that government's influence on employment trends is very small, if not negligible. since we're talking about government efforts in general, the argument applies to the specific government treated in the problem. if you're going to say that the government in question is somehow exempted from this reasoning, you need to justify that exemption. you DON'T have to justify including government X in a general statement about governments, because, well, government X is a government.

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here's why the wrong answers are wrong.

(a)
mostly irrelevant; any connection is far too distant to matter.
if anything, this choice strengthens the argument, because, if there will be fewer immigrants to potentially fill jobs, then the "out-of-work young people" will have more chances to fill those jobs themselves.

(c)
irrelevant.
this choice deals only with the best of the available positions, and has no relevance at all to the majority of the positions.
that's enough to strike this choice already, but, if you want another reason, note that the passage only claims to deal with "many of" the jobs anyway - a category that could certainly exclude the best positions.

(d)
weakens the argument VERY slightly.
"a small proportion" is the death blow here.

(e)
actually strengthens the argument.
if lack of awareness is the problem, then the projected convening of employers and educators is targeted at exactly that sort of thing.