Rome's military and administrative strength allowed it to endure several crises until, finally, waves of invaders brought about

Rome's military and administrative strength allowed it to endure several crises until, finally, waves of invaders brought about its fall.
A) Rome could survive the attacks of invaders thanks to its powerful army and governmental system; however, several crises ultimately caused its fall.
B) Although waves of invaders were able to make Rome surrender after several crises, they eventually failed to weaken Rome's military and administrative powers.
C) If it had not been for Rome's military and administrative strength, it could not have survived even until the attack of invaders.
D) Rome was able to handle many crises thanks to the power of its army and governmental system, yet it ultimately collapsed as a result of the attacks of the invaders.
E) The invaders eventually succeeded to conquer Rome after some crises no matter how powerful its military and administration were.