Large scale mining of metal and coal in the region has led to both

Question

Large scale mining of metal and coal in the region has led to both acid rock drainage,  acid water flowing out from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining, altering  the receiving environment to its detriment, but are harmless if collected and disposed of in time.

(A) acid water flowing out from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining, altering

(B) which is the outflow of acidic water from abandoned mines, as well as the deposition of tailings, elements or compounds uncovered during mining, altering

(C) the outflow of acidic water from abandoned mines, the deposition of tailings, elements or compounds uncovered during mining, which may alter

(D) acid water flowing out from abandoned mines, the deposition of tailings, elements or compounds uncovered during mining, which may alter

(E) which is the outflow of acidic water from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining, which may alter

aragonn · Accepted Answer

Official Explanation:

Answer - E 
Concepts tested: Modifiers, Parallelism, Idioms

A - ‘altering…’ modifies the entire preceding clause, whereas it must modify ‘tailings’.
B – Same as A. Additionally, the use of ‘both’ and ‘as well as’ in B is redundant. 
C - ‘and’ is missing before ‘the deposition’ and are, therefore, run-on sentences. 
D – Same as C 
E – This option uses the right modifier as the “Which” refers to acid rock drainage.

medus18 · Answer

"Both" requires "and" and phrase "Which may alter" is parallel to "are harmless if collected". So I will go with E here

Posted from my mobile device

Akash720 · Answer

+1 for E

(A) acid water flowing out from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining,  altering

(B) which is the outflow of acidic water from abandoned mines,  as well as  the deposition of tailings, elements or compounds uncovered during mining, altering -->  Both X as well as Y is wrong idiomatic usage

(C) the outflow of acidic water from abandoned mines,  the deposition of tailings , elements or compounds uncovered during mining,  which  may alter

(D) acid water flowing out from abandoned mines,  the deposition of tailings , elements or compounds uncovered during mining,  which  may alter

(E) which is the outflow of acidic water from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining, which may alter
-->  We have two modifiers here  " which is the outflow of acidic water from abandoned mines "  modifying  -  acid rock drainage 
  and  " elements or compounds uncovered during mining "  modifying  -  the deposition of tailings .  Here, 'which' is modifying both of them as we can observe in the non underlined part of the sentence  - but   are   harmless ( plural   are   signifies both X and Y are modified by ' which ')

aragonn · Answer

Akash720  both used for 2 things only..... I think u should revisit your answer

Posted from my mobile device

Akash720 · Answer

Thanks  aragonn , I hope I've corrected my mistake.

tarunanandani · Answer

IMO E.

Options B, C and D are wrong because of idiom error, 'both X and Y.
And I think Option A is wrong for two reasons: 'acid water flowing...' seems to be an item in the list,  both X, Y and Z  and doesn't clearly modifies 'acid rock drainage'; if altering is used then there is  no clear plural noun  for 'but are harmless...' clause.
 Option E  corrects these two mistakes by using 'which is...' to modify 'drainage' and by using 'elements... which may... but are...' to make clear: 'elements' as the plural noun subject for 'but are...' clause.

shaarang · Answer

+1 for E, however, I'm not too pleased with the option itself.

Isn't there a parallelism error here? Shouldn't it be "drainage of acid rocks" and "deposition of tailings" or "acid rock drainage" and "tailing deposition"?

Looking forward to the OA and a correction if my reasoning is incorrect.

tarunanandani · Answer

Hi,

There isn't a parallelism error because the sentence is comparing same entity, noun. For parallelism to hold the noun form  need not follow same structure .
Same goes for participles, V+ed particle can be in parallel with V+ing participle when they describe a common entity. 
For participles you can visit this post for further detail:  https://gmatclub.com/forum/verb-ed-verb-ing-can-be-parallel-126923.html

Hope this helps!

dimmak · Answer

In E: "..., and the deposition of tailings, elements or compounds uncovered during mining, which may alter"

"which" can modifies "mining" or "elements or compound" am I right? Is there ambiguity here??

Thanks

anand0811 · Answer

which ,which rule not applicable here.

mining,which.....as per my understanding which should modify mining

DmitryFarber · Answer

If we look at the non-underlined text at the ends, we see that we have parallel verbs: which MAY ALTER, but ARE harmless. This means that "which" must apply to the subject of these two verbs. Since we need a plural subject for "are," the subject must be "tailings." (The lack of an Oxford comma is a clue that "elements or compounds uncovered during mining" is another modifier for "tailings." We do NOT have a list of 3 things: tailings, elements, or compounds.)

I'll leave it to you all to decide if the GMAT would ever use "which" to refer back to a distant noun that is itself part of a modifier ("of tailings"). I'd guess not, but we can still do some detective work and get this one right.

I'll leave it to you all to decide if the GMAT would ever use "which" to refer back to a distant noun that is itself part of a modifier ("of tailings"). I'd guess not, but we can still do some detective work and get this one right.

Tarungaur · Answer

Hi  CrackVerbal  team

Can you please explain option E

which is the outflow of acidic water from abandoned mines, and the deposition of tailings, elements or compounds uncovered during mining,  which may alter ,

In the above option, which should refer to the preceding noun? What is "which" referring back to specifically.

Thank you.

Large scale mining of metal and coal in the region has led to both

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Large scale mining of metal and coal in the region has led to both

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