The difference in the twentieth-century mass killings in the nations of Cambodia and Yugoslavia were different because D. widespread violence in Yugoslavia was mostly motivated by ethnic and religious hatred.
The mass killings in Cambodia were mostly as a result of a political party, the Communist Khmer Rouge, killing hundreds of thousands in order to maintain control over the nation.
This was different from mass killings in Yugoslavia which was fueled by hatred of other ethnic groups by the Serbians who were mostly Christians and so against the Muslim Bosnians.
In conclusion, option D is correct.
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