With an Evaluate the Argument question, we have to keep in mind that it's aaaaalll about that Conclusion! This isn't like a Weaken or a Strengthen in which some tiny piece of evidence will twist around and be part of the correct answer, unexpectedly.

Evaluate questions are easy if you keep in mind that you are here to evaluate the Conclusion sentence and that's it!
So let's break this one down!

Evidence: US govt gets $$$ info (to help students choose).

Conclusion: Students who choose for $$$ / not will

Ridiculous emojis aside, we can see the scope of this conclusion is about what the RESULT will be when students base their CHOICE on $$$$$. Definitely the correct answer needs to match that scope!

Let's look at the scope of each answer choice:

A) What is the number of colleges that will be covered by the government initiative? (the number affected is not part of the conclusion's scope)
B) Currently, what proportion of students who struggle in college also struggle in their careers? (better than A, but still not great, but let's keep it for now)
C) Do some students currently pick their subject fields based on their passion? (decent, related to students, let's keep it)
D) Are there currently any good websites providing average salaries data for the students? (what the heck?! this has absolutely nothing to do with the students and their choices)
E) How will the government ensure that the data published on the salaries of the students is not biased against certain colleges? (who cares about the data; we're interested in the students' choices)

The Final Two here are (B) and (C). Let's answer these hypotheticals:

B) Currently, what proportion of students who struggle in college also struggle in their careers?

Let's say 100% who struggle in college struggle in careers. Or let's say 0% who struggle in college also struggle in their careers. This has no bearing on whether students who pick $$$ over passion will succeed.

C) Do some students currently pick their subject fields based on their passion?

Let's say yes, some students DO pick their major based on ; it doesn't have a huge impact. BUT, what if NO students choose for passion? Well if none choose for passion, and they ALL choose for $$$$, then the author's argument is greatly weakened!!! In that case, there wouldn't even be a dichotomy -- no choice at all! They ONLY choose for $$$. So how could choosing for $$$ over even be possible?

Because one way to answer (C) has a major impact on the Conclusion, this is the correct answer. Playing "Devil's advocate" for each "side" of the Evaluate answer choice can help you see which one is most relevant to the Conclusion.
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that was a really insightful answer

Conclusion: Students who pick their field based primarily on post-graduation salaries, as opposed to passion for a field, will struggle in both school and career.

Which of the following options would help most to evaluate the given argument?

A) What is the number of colleges that will be covered by the government initiative? - irrelevant.
B) Currently, what proportion of students who struggle in college also struggle in their careers? - irrelevant in evaluating the conclusion.
C) Do some students currently pick their subject fields based on their passion? - if this is true, then one can certainly infer that the new scheme used by the government certainly helps some students pick their true passion, thereby weakening the conclusion. If (C) is false, however, then one can reasonably support the conclusion. Hence, (C) does indeed help us evaluate the conclusion. Therefore, (C) is the right answer choice.
D) Are there currently any good websites providing average salaries data for the students? - irrelevant.
E) How will the government ensure that the data published on the salaries of the students is not biased against certain colleges? - irrelevant.