After the Arab conquest of Egypt in A.D. 640

[sinhavis]

After the Arab conquest of Egypt in A.D. 640, Arabic became the dominant language of the Egyptians, replacing older languages and writing systems.

(A) became the dominant language of the Egyptians, replacing older languages
(B) became the dominant language of the Egyptians, replacing languages that were older
(C) becomes the dominant language of the Egyptians and it replaced older languages
(D) becomes the dominant language of the Egyptians and it replaced languages that were older
(E) becomes the dominant language of the Egyptians, having replaced languages that were older

Internet SC quiz

OA is A
Why "becomes" is wrong here and "became is correct". Also why replacing is prefered over it replaced as in D

[StaceyKoprince]

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