I would go with D.

imo D

Concept tested: subject verb agreement

Efforts to equalize the funds available to school districts, a major goal of education reformers and many states in the 1970's, has not significantly reduced the gaps existing between the richest and poorest districts.

Here the subject ''Efforts'' is plural whereas its corresponding verb ''has'' is singular

Hence, we should either make the subject singular or make the verb plural

Choices D and E do make the verb plural so we eliminate A,B and C

Now, between D and E

Choice E is wordy and awkward
D is concise and clear

Please note: In choice D, do check 'gap that exists' again singular 'gap' with singular 'exists'. This is also testing the subject verb agreement concept.

has..SV prob...ABC ..out
E..wordy
SO, IMO D.

imo:D

D should be the answer

(D) have not significantly reduced the gap that exists
(E) have not been significant in a reduction of the gaps existing

Adverb usage is also tested

In D, adverb "significantly " correctly describes the verb "reduced"

while in E, significant describes noun "efforts" and adds no additonal meaning to the statement

IMO D

guys, my question was "can anyone write original sentence with "efforts" as subject?" before it is iverted..

Efforts to equalize the funds available to school districts, a major goal of education reformers and many states in the 1970's, have not been significant in a reduction of the gaps existing between the richest and poorest districts.

can anyone write original sentence with "efforts" as subject?[/quote]

Efforts that are used to equalize the funds available to school districts , a major goal of education reformers and many states in the 1970's, have not been significant in a reduction of the gaps existing between the richest and poorest districts.

Try this ?

is the use of the simple present "exists" after the present perfect "have reduced" correct in choice D?

Thanks

'Efforts to equalize the funds available to school districts, a major goal....".

The phrase here is considered as a single noun (a major goal). In that case, don't I have to take 'has' instead of 'have'. Please correct me if I am missing something.

Please help

Here "Efforts" is the subject noun, not 'a major goal'. So, according to subject-verb agreement, 'have' has to be used.