We can eliminate A and B, because they are comparing ministers to the year 1977, and much is not used for countable things.
E is also incorrect because of 1977's is redundant.
We can eliminate C because what cannot refer to percent, the survey or the ministers. This leaves D.
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To find the best answer, we find four wrong answers, by POE. All the others are wrong for reasons outlined in earlier posts. I’m not a native speaker of English, but I know there is nothing wrong with ‘double the figure for.’


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AKASHSURANA , option E has other problems, but the easiest to spot is a phrase that is always wrong on the GMAT: "that of 1977's.

GMAC considers the phrase redundant: GMAC allows the use of only one marker of possession, and the phrase "that OF 1977's" uses two markers.

• on the GMAT, do not use possessive marker OF and ['s] in the same phrase
-- The word OF indicates possession: the daughter of the king
-- The use of [apostrophe + S] ['s] also indicates possession: the king's daughter
-- On the GMAT, we can use one or the other, but not both at the same time.

• Use X's Y or Y of X, but not both

Anthony [X] has a cousin [Y] whose name is Marc.

-- Correct: X's Y
Marc is Anthony's cousin.
Anthony's cousin Marc lives in my city.
(Only ['s] is used.)

-- Correct: Y of X
Marc is a cousin of Anthony.
Marc, a cousin of Anthony, lives in my city.
(Only OF is used.)

-- Wrong: Y of X's
Marc is a cousin of Anthony's.
Marc, a cousin of Anthony's, lives in my city.
(Both ['s] and OF are used. Not okay on the GMAT.)

Option E is redundant on the GMAT because it uses both an OF and ['s]:
a number double
that of 1977's

We need either
-- that of 1977
or
-- 1977's [number]

Hope that helps.
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