Which of the following sentences best describes the beginning of the Askumite Empire?

King Ezana led the Nubians in a failed war against the Askumite conquerors.
In a series of violent conflicts, Askumites conquered the Nubians and settled along the Nile.
Askumites settled as traders in Nubian territory and eventually became powerful enough to conquer the Nubians and take over.
Civil war disrupted trades routes between Babylon and Nubia and the Askumites capitalized on this weakness.