Which statement best describes how rulers such as cyrus the great and darius were able to rule the diverse and expansive persian (achaemenid) empire of the 500s and 400s bce?
a) persia permitted christian groups to worship freely.
b) persian military forces drafted all men under 30 into service.
c) persia allowed conquered areas to rule themselves on local matters.
d) persian armies crushed all possible resistance to prevent future rebellions.