Why Did Justinian's Reconquest of the Western Roman Empire Fail

Multiple Choice

Why did Justinian's reconquest of the Western Roman Empire fail?

A) Justinian codified Roman law,which made a permanent merger impossible.
B) Western Christians no longer felt kinship with eastern Christians,and they fought against Justinian from within.
C) The costs associated with conquering and defending the vast western empire were too great given Justinian's military commitments elsewhere.
D) Constantinople fell to Persian invaders and brought an end to the Eastern Roman Empire.
E) Justinian was forced to withdraw his army to meet the mounting Islamic threat from the south.