Even though it is officially an LSAT question, practicing LSAT critical reasoning and reading comprehension is actually really helpful for the GMAT. They are essentially the same as GMAT questions except they are more difficult, so they are valuable for people aiming for a 700+.
Let's go through the answer choices
A) is wrong because it is too strong of a claim. The prompt only says that "SOME environmentalists environmentalists QUESTION the prudence of exploiting features of the environment", so it would be too much to infer this
B) Since the prompt states that "Many environmentalists claim that because nature has intrinsic value it would be wrong to destroy such features" it would be logical to infer that Some appeal to noneconomic justifications
C) is wrong because again it goes to far. There is nothing in the propt that would allow us to infer anything about most scientists
D) is wrong because just because many environmentalists provide noneconomic justification doesn't mean that is the ONLY justification they provide
E) is wrong because it outside the scope. There is nothing in the propt that allows us to determine what would be a sound justification or not, there is no mention of the sort.
Thus, the answer choice is B. This question is a great example of how the simplest answer that is closest to the prompt can often be the correct one.