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

Only the right answer will accurately describe what kind of support, conclusion, or background the claim mentioned in the prompt is.

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

there is unlikely to be a widespread, grassroots effort for new, more restrictive air pollution controls at this time.

Professor Shanaz: [SUPPORT]. Although [BACKGROUND], most people are currently well aware that [SUPPORT]. Hence, [CONCLUSION].

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

(A) …in support of the claim that contaminated water currently presents…

This started off okay, but that’s not the conclusion it’s supporting.

(B) …in support of the claim that there is unlikely to be a widespread…

This gets the “role” right, and it matches the conclusion in the passage. A sure winner.

(C) …to explain the current public awareness…

Nope, even if you’re okay with “explain”, it should quote the conclusion next. But “the current public awareness” isn’t what gets explained. The author just stated that like a fact, without giving support for it.

(D) …indisputable evidence…

That’s really extreme wording that doesn’t map to anything stated by the author. Their conclusion was only that something is “unlikely”.

(E) It is the main conclusion…

Nope, no support was given to back it up, so it’s not a conclusion.

(B) is the correct answer.