I think we should not miss the fine point of the text. Please read the underlined portion yet again and you will find that this is testing a style error i.e. wrong word order.
The question is: where was the library? : It was in Alexandria; it was the largest library of the ancient world; we should not take to think that the ancient world was at Alexandria, giving an absurd meaning
That is the reason A and B are thrown out.
C is wrong because of redundancy, as all have pointed out
D is the right choice
E tends to distort that meaning that there were many libraries in Alexandria and the one that was the largest was destroyed , leaving smaller ones without destruction, This meaning is not what the text intends to convey.
Incidentally, is a B run-on? A run-on is one where the conjugation is wrong. Either a comma is simply used where a conjunction or a different punctuation such as a period or semicolon is required. B is amply conjuncted with a coordinate conjunctiuon ‘and’
. The first portion is a full sentence with a subject (the destroying of) and a full verb (resulted) and the second part is a full clause. So how is B a run-on?
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