D. England
All of the other three were actively competing for Korea at the time along with America as well.
They were intimidated by violent threats and actions.
During the 1960's, African-Americans still faced a significant amount of discrimination in American society. This included threats and physical violence. Groups like the Ku Klux Klan, a white supremacist organization, used fear tactics in order to stop African-Americans from voting during this era. This included death threats or actually violence if they showed up to the polling place.
The Kings had the most power in feudal Europe. They controlled all of the land. They had the power to distribute land to nobles, who, in turn, would distribute that land to knights and vassals.
As of China, they use the system called "mandate of heaven" to select their emperor. The Mandate of Heaven is like god. The gods select who should be their next emperor