Why Did Justinian Try to Reconquer the Western Roman Empire

Why did Justinian try to reconquer the western Roman Empire?

A) Because the Persians had been defeated in the East, so he could safely launch military expeditions to the West.
B) Because his empire required continuing conquests in order to prosper.
C) Because he sought to reunify the increasingly fragmented Roman Empire.
D) Because he needed to keep his army as far away from his capital as possible.
E) Because he believed that he should be the head of a unified Christian Church.