What was constantine's primary motivation in moving the capital to byzantium?
a. it was a strategic site which linked the western empire with the increasingly wealthy east
b. it made it easier to protect the vast empire with a more centralized capital city
c. he wanted to build a new city to honor the christian god, as he had just converted to christianity
d. the city of rome had been sacked by the visigoths and it was too expensive to rebuild on that site