SC from Gmat Prep

[wrtau23]

Did a search and did not see this one posted, feel free to post link if it has already been posted.

While they remove carbon dioxide from the air, conserve soil and water, and house thousands of species, forests also supply potentially valuable pharmaceuticals, and, as sources of building material and firewood, that provide employment for millions worldwide.

A. pharmaceuticals, and, as sources of building material and firewood, that provide
B. pharmaceuticals, and sources of building material and firewood, are providers of
C. pharmaceuticals and, as sources of building material and firewood that are providing
D. pharmaceuticals and sources of building material and firewood, for providing
E. pharmaceuticals and, as sources of building material and firewood, provide

I choose D which was wrong.
OA is E

Any assistance is appreciated.

[mowghli]

A/C out since its not firewood providing employment
Looking at parallelism,
forests supply and <....>, I believe it should be provide.

Eliminate B/D for not parallel.
Hence E.

[ankit1383]

A. pharmaceuticals, and, as sources of building material and firewood, that provide

that after comma modifies......??
which after comma modifies the last preceding noun...
That without comma does the same.....

Please answer this...

[vivek.kapoor83]

'that' after comma is not acceptable because it is essentinal info for the sentence and 'that' should be used without comma.
We use 'which' when it is non-essential info for the sentence.
'that' after comma converts sentence into non-restrictive modifier which is not acceptable as info give after that is essential