The Weakness of the Byzantine Empire in the Eleventh Century

The weakness of the Byzantine empire in the eleventh century was caused,in part,by:

A) a series of ill kings who did not reign for very long.
B) diplomatic overtures it made to the Islamic caliphate.
C) a series of raids along the northern border of the empire.
D) a drastic reduction in trade due to closing markets in the East.
E) the debasing of the empire's gold coinage.