Answer: The Monroe Doctrine is the best known U.S. policy toward the Western Hemisphere. Buried in a routine annual message delivered to Congress by President James Monroe in December 1823, the doctrine warns European nations that the United States would not tolerate further colonization or puppet monarchs.
A thing that wouldn't be necessary condition for the growth of an empire would be internal revolutions and revolts - D.
This option, compared to the others, actually underminens the possibility of success within one empire after some time as undermining authority and creating revolutions doesn't help when creating an empire.