The decline of the mountain yellow-legged frog in the high reaches of the Sierra Nevada has become severe enough for the United States Fish and Wildlife Service quite possibly to list it as an endangered species in the near future.

Intended Meaning

The sentence is talking about two things. 1. The decline of frog. 2. United States Fish and Wildlife Service could enlist the frog as an endangered species. These two things happens independently and the first one is not deliberately causing the second.

(A) severe enough for the United States Fish and Wildlife Service quite possibly to list it
Incorrect : This option alters the intended meaning. The intended meaning is that the United States Fish and Wildlife Service could list the frog as endangered because of the decline in its numbers. This option implies that the frog intended to be severe enough to be listed
(B) severe enough so that the United States Fish and Wildlife Service could well list them
Incorrect : 1. Meaning issue 2. The pronoun "them" cant refer back to frog as frog is singular
(C) severe enough for it quite possibly to be listed by the United States Fish and Wildlife Service
Incorrect : Same meaning issue as in A
(D) so severe that the United States Fish and Wildlife Service could well list it - Correct. The pronoun it refers back to its logical antecedent "frog"
(E) so severe that they could well be listed by the United States Fish and Wildlife Service
Incorrect : The pronoun "they" cant refer back to frog as frog is singular

I had to go between D and E, but in E, they (which is the wrong pronoun) should refer to the frog(which is singular!!)

arent we talking abt yellow legged frog species here?

I would prefer D here.

In E there is S-V problem (we are talking about a # legged frog) and also E is passive compared to D

Answer is D!!

E is wrong because of the "they" which is wrong in reference to the
"The decline of the mountain yellow-legged frog" .

The correct statement for E should be
-so severe that they could well be listed by the United States Fish and Wildlife Service so severe that it could well

Answer D

clearly D

In E they is plural and where as frog is singular

yes, the OA is D
but why not A????

severa enough is not idiomatic but "so .....that" is.

D is clear and concise.

I'm curious too. Why does the it refer to the frogs rather than the decline?

The decline [of the mountain yellow-legged frog in the high reaches of the Sierra Nevada] has become severe enough for the United States Fish and Wildlife Service quite possibly to list it as an endangered species in the near future.

Removing the unnecessary part in the above statement in bold and considering that the subject of the sentence."it" refers to decline.
Am i missing something?
Please help.

"x...enough" illogically implies that the decline was a goal.
This is from manhattan.

thanks. your posts are always "value added" ones.

+1 D

so (adj.) that is the correct idiom.
In E, they doesn't have a clear antecedent.
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Answer is D. Strucute is of the form:SO X that Y- So Severe that the united states----

Appreciate experts views on the use of pronoun 'it'. To me it is ambiguous.

Pick the best out of the options given and move on to the next question. The clocks ticking
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i disagree [while i am practicing]. this is an official Q. ambiguity must be removed.

I was able to eliminate E and B based on the fact that they and them are wrong pronouns references .
C is passive and not preferred , but i cannot seem to eliminate OA a ?

what is wrong with A?

is it the idiom which is wrong ? so X that why ?

whats wrong with ''has become severe enough''?