What was the significance of the edict of milan, announcing tolerance of christianity, and then the adoption of christianity as rome’s official religion?

a: it caused a holy war between pagan and christian elements of the roman empire.
b: it meant that wherever the roman empire expanded, christianity would go there also.
c: it ensured that all future emperors would be appointed by the christian church.
d: it required all members of roman society to become practicing christians.