GMAT Sentence Correction (SC) | The paradox of the Roman empire’s history is marked

The paradox of the Roman empire’s history is marked by the fall of the western part around the 5th centaury A.Dwith several regions succumbing to cross border terrorism and internal insurgency, breaking into independent kingdoms, the rise of the eastern part, with the empire fire-walling the crises, and retaking most of the lost territories to establish a firm rule of over most of the Eastern Europe for another six to seven centuries

(A) with several regions succumbing to cross border terrorism
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