How will the right answer fit in terms of support and conclusion?

Only the right answer will use the same kind of support and conclusion that the passage uses.

Highlight the main conclusion in the passage, if there is one:

we should be suspicious of the newspaper reporter’s claim that the tracks are in poor condition.

[SUPPORT]. Thus, since [SUPPORT], [CONCLUSION].

Map the wording of the answers to the wording of the passage:

(A) …So I will probably not…for whenever I do…

This conclusion and support both use wording that doesn’t map. There’s no “probably” or any synonym for it in the author’s conclusion. And the second premise was about “no bias”, not a rule about “whenever” something happens.

(B) …who has no vested interest…So we should be skeptical…inspected the bones carefully.

All of this maps to matching statements in the passage, and it doesn’t bring in anything new that doesn’t echo the passage. You’d love to be confident about that, so you can pick this and keep moving.

(C) ..Thus, we should consider the bridge safe.

The conclusion is supposed to say we should doubt or “be suspicious” of some counter-argument. This doesn’t match.

(D) …we should accept that the prime minister is in poor health.

This one is also missing something that means “we should be suspicous” of someone’s counter-argument.

(E) …because the salesperson is biased, we can discount that claim.

Nope, the conclusion discounts someone’s claim because someone else is not biased. That may have sounded close to you, but it doesn’t match like (B) does.

(B) is the correct answer.