Here's the
official explanation provided by the GMAC for this question:
According to the sentence, after 640 AD, Arabic became the dominant language in Egypt. It replaced older languages and writing systems. The verb
became refers to that distant past, and the phrase
replacing … writing systems modifies the noun
Arabic, the subject of the sentence. The adjective
older correctly modifies both
languages and
writing systems.Option A: Correct. The sentence states a historical fact with clarity, precision, and correct grammar and usage, as explained above.
Option B: This answer choice has two flaws. It uses the word
systems, which adds nothing significant to
languages. The clause
that were older modifies
language systems only but should also modify
writing systems; it represents no improvement over the given sentence, which applied
older logically to both
languages and
writing systems.
Option C: The present tense
becomes is inconsistent both with the past tense
replaced and with the reference to a distant past. The pronoun
it refers to
Arabic, which is the subject of both
becomes and
replaced. Since there is no comma preceding [color=#ed145b]and, the pronoun
it should be omitted.[/color]
Option D: The phrase
languages that were older and writing systems is awkward and represents no improvement over the given sentence, which applied
older logically to both
languages and
writing systems. The present tense
becomes should be past tense, referring to a distant past as does the past tense
replaced.Option E: The present tense
becomes should be replaced by the past tense, referring to a distant past. Arabic’s becoming the dominant language was precisely contemporaneous with its replacement of older languages, so
having replaced indicates, illogically, that when Arabic became the dominant language, it had somehow already replaced the other languages. As previously explained,
languages that were older fails in that
older does also not modify
writing systems, contrary to what was likely intended.
The correct answer is A.
Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.