Question

One reason the Byzantine Empire outlived the Western Roman Empire was that __________.

Answer 1

The answer is A)
There are many reasons why the Western Roman Empire failed (that were missing for the Byzantine Empire) and one of them was threat the Western, but not the Eastern Empire, was repeatedly attacked by the Germanic tribes from the north. 

One reason the byzantine empire outlived the western roman empire was that political organization was much better, which reduced infighting among members. 

Answer 2

I believe the answer is D. 

hope this helps :)