As well as vitamin C and phytonutrients, blueberries are a source of nutrients known as antioxidants.

A) As well as vitamin C and phytonutrients, blueberries are a source of
Wrong

B) Besides vitamin C and phytonutrients, also blueberries are a source of
Wrong

C) Blueberries are a source not only of vitamin C and phytonutrients, but also
Wrong

D) Blueberries are a source not only of vitamin C and phytonutrients, but also of
Correct - not only of... but also of

E) Blueberries are a source of not only vitamin C and phytonutrients, but, as well, of
Wrong

IMO D, OA?

DanaJ wrote:Source: Veritas Prep

As well as vitamin C and phytonutrients, blueberries are a source of nutrients known as antioxidants.

A) As well as vitamin C and phytonutrients, blueberries are a source of
B) Besides vitamin C and phytonutrients, also blueberries are a source of
C) Blueberries are a source not only of vitamin C and phytonutrients, but also
D) Blueberries are a source not only of vitamin C and phytonutrients, but also of
E) Blueberries are a source of not only vitamin C and phytonutrients, but, as well, of

Experts: only Veritas Prep experts, please!

The question is a remake of a gmatprep question.

The rule:

As well as X, Y is also a source of Z.
==> It means that both X and Y are the source of Z.

Besides X, Y is also a source of Z.

=> Both X and Y are the source of Z.

--> Eliminate A and B.

Then apply not only....but also.

Answer is D.

Good way to deal with such questions is to break the question up into:

Rest of the sentence..not only X, but also Y.

So, Rest of the sentence should make sense with both X and Y

Apart from D, C could only be the other choice that comes a bit close. Lets analyze C:

Rest of the sentence (Blueberries are a source) not only X (of vitamin C and phytonutrients), but also Y (nutrients known as antioxidants).

With X, the sentence would read: Blueberries are a source of vitamin C and phytonutrients - making sense.
With Y, the sentence would read: Blueberries are a source nutrients known as antioxidants - not making sense, since the preposition of is missing.

Hence, C is not correct.

Could the missing 'of' in the second part of choice C ever be understood?

Sure, in many cases:

This scandal smacks not just of deceit but (of) corruption as well.

OA is D.

Nice work on this one guys - it is very similar to what can be found on the GMAT...

Correct answer: (D)

Solution: In this Equivalent Elements question, the priority is making sure that "vitamin C and phytonutrients" have the correct relationship to what they're being compared to, "nutrients known as antioxidants." Answer (D) is correct because it uses a correct "not only/but also" construction and "of vitamin C" is parallel to "of nutrients." Answer (A) is incorrect because "As well as vitamin C and phytonutrients" is misplaced and confusing. Answer (B) is incorrect because it is awkward and the relationship between the various nutrients remains unclear. Answer (C) is incorrect because it lack a final "of" to complete the parallelism between "not only of" and "but also of." Answer (E) is incorrect because "as well" is the wrong pair of words to use with "not only." The idiom is "not only/but also."

DanaJ wrote:Source: Veritas Prep

As well as vitamin C and phytonutrients, blueberries are a source of nutrients known as antioxidants.

A) As well as vitamin C and phytonutrients, blueberries are a source of
B) Besides vitamin C and phytonutrients, also blueberries are a source of
C) Blueberries are a source not only of vitamin C and phytonutrients, but also
D) Blueberries are a source not only of vitamin C and phytonutrients, but also of
E) Blueberries are a source of not only vitamin C and phytonutrients, but, as well, of

Experts: only Veritas Prep experts, please!

The correct answer is D.Since the Idiom is NOT ONLY x....,BUT ALSO y;where x&y must be in the same parts of speech,or parallel.A is redundant(as well as & and) B changes the meaning,In C of is omitted after but also,In E correct idiom has not been used.
Dinesh Kumar Upadhyaya

D....Since the Idiom is NOT ONLY x....BUT ALSO y

As well as vitamin C and phytonutrients, blueberries are a source of nutrients known as antioxidants.

A) As well as vitamin C and phytonutrients, blueberries are a source of
Incorrect, Meaning is not conveyed properly.
B) Besides vitamin C and phytonutrients, also blueberries are a source of
Incorrect, Unidiomatic
C) Blueberries are a source not only of vitamin C and phytonutrients, but also
Incorrect, Also 'of' seems to be missing.
D) Blueberries are a source not only of vitamin C and phytonutrients, but also of
Correct, Precise and meaning is conveyed well.
E) Blueberries are a source of not only vitamin C and phytonutrients, but, as well, of
Incorrect, Wordy and imprecise.

I could narrow down to C & D.
But D wins as it has the "of"missing in c and hence maintains the parallel structure of the sentence.

It's D

DanaJ wrote:Source: Veritas Prep

As well as vitamin C and phytonutrients, blueberries are a source of nutrients known as antioxidants.

A) As well as vitamin C and phytonutrients, blueberries are a source of
B) Besides vitamin C and phytonutrients, also blueberries are a source of
C) Blueberries are a source not only of vitamin C and phytonutrients, but also
D) Blueberries are a source not only of vitamin C and phytonutrients, but also of
E) Blueberries are a source of not only vitamin C and phytonutrients, but, as well, of

Experts: only Veritas Prep experts, please!

D it is!!

IMO D.... This was damn easy.