Answer:
Serbia
"Murder" and "Ethnic Cleansing"
C. felt too guilty to continue with their plans.
Explanation:
Ethnic Cleansing: According to wikipedia.com, "Ethnic cleansing is the systematic forced removal of ethnic, racial and/or religious groups from a given territory by a more powerful ethnic group, often with the intent of making it ethnically homogeneous." This is a light description of Genocide, which is the intentional and planned destruction of an ethnic group by another.
Murder is also deliberate killing of some person(s). So, looking at holistically, what happened was a genocide.
This "ethnic cleansing in the Bosnian War (1992–95) occurred during the conflict as large numbers of Bosnian Muslims (Bosniaks) and Bosnian Croats were forced to flee their homes or were expelled by the Army of Republika Srpska and Serb paramilitaries." according to wikipedia.com. It was a war of shame on a large scale.
