vote for C

neither A nor D because of demonsrate, we need demonstrates or demonstrated
in B both of is not || with and ( no preposition before and)
in E both their and... no pronoun before and

Clock,

Can you explain bit more how you arrived at your choice?

Ta

imo d

well, but i am bad expounder
A)the use of toxic lead and.......demonstrate, here is wrong usage of verb demonstrate
we need demonstrates, or at least demonstrated
D) the same problem with worling verb
toxic lead.....demonstrate-wrong verb
B)both of their aqueducts and their private homes by ancient Romans
i believe that we need preposition-of- before and in the second part of the idiom
both of their...and of their.
i am not too sure. as i saw ||-forms where they omit preposition. and still consider that correct
but in other options they follow strict ||-ism
E)again the problem with idiom both...and in that two parts are not ||
both their aqueducts and private homes demonstrates
in e they omit second their,before and it is not criminal but again in other versions they follow strict ||-ism
so left with C
in C they avoid usage of preposition of inserting it before both, and put their in both part of the idiom
of both their aqueducts and their private homes
By the way what is oa,
perhaps, i am proving that wrong answer is correct

Metals, pigments and other chemical substances used by ancient cultures were not always benign, as the use of toxic lead by ancient Romans in the plumbing-a word derived from the Latin word for "lead"-of both their aqueducts and their private homes demonstrate.

(A)the use of toxic lead by ancient Romans in the plumbing-a word derived from the Latin word for "lead"-of both their aqueducts and their private homes demonstrate
(B)demonstrated by the use of toxic lead in the plumbing-a word derived from the Latin word for "lead"-both of their aqueducts and their private homes by ancient Romans
(C)demonstrated by the toxic lead that ancient Romans used in the plumbing-a word derived from the Latin word for "lead"-of both their aqueducts and their private homes
(D)toxic lead used by ancient Romans in the plumbing-a word derived from the Latin word for "lead"-both of their aqueducts and of their private homes demonstrate
(E)the use by ancient Romans of toxic lead in the plumbing-a word derived from the Latin word for "lead"-of both their aqueducts and private homes demonstrates


Whenever you find the answer options wherein the prepositional phrases are interchanged with one another then you must focus on:
1. whether the meaning of the original sentence or the intended logical meaning is distorted.
2. whether interchanging of the phrases leads to awkward sentence construction or no meaning at all.

Also do not forget to check whether other grammar rules are violated.


A - clearly a subject-verb agreement problem. The subject in the dependent clause followed by as "the use of toxic lead" does not agree with "demonstrate". Also, use of passive voice. "It is demonstrated by the use of toxic lead by Romans" would have been better than "Toxic leads use is demonstrated by Romans". However, if you find even a single grammatical flaw, dont bother to look for another.

B - Awkward Sentence Construction. Active Voice makes it look better though. One more thing, if you find something common amongst the answer choice, dont bother to look at it, for example, the origin of the word plumbing. So if that is removed, the answer choice looks something like this
"demonstrated by the use of toxic lead in the plumbing both of their aqueducts and their private homes by ancient Romans". "In the plumbing both of" does not make sense. Also, placing the modifier "by ancient Romans" at the end of the dependent clause does not make sense. It should be as close to "the use of toxic lead" as possible for it to match with the independent clause mentioned earlier "metals... used by ancient cultures. Also, this would make the pronoun "their"
to relate better.

C - No grammatical flaw, Active Voice.

D - Combines all possible flaws mentioned above: Subject Verb Disagreement, Awkward Sentence Construction. Unnecessary use of "of".

E - Awkward Positioning of the Prepositional Phrases/Modifiers. "The use..by Romans..of Toxic Lead ... in Plumbing ...of aqueducts and ...demonstrates. Does the "use by Romans demonstrates" that the "use of metals was benign"? No, the use of toxic lead indicates that. To match with the previous dependent clause, the use should be associated with toxic lead. Subject Verb Disagreement is corrected here but the subject itself does not make sense.

Hope this helps.