What was the significance of the Battle of Milvian Bridge?

A. Emperor Constantine won control of the empire after painting a Christian symbol on his soldiers' shields.
B. Ostrogoth forces finally forced the Roman emperor to surrender, which brought about the fall of Rome.
C. Alexius I led Christian soldiers who had been sent by the pope to conquer the city of Jerusalem.
D. Augustus Caesar ended years of civil war when he conquered the forces of Marc Antony and Queen Cleopatra of Egypt.