What were the Killing Fields of the Khmer Rouge?

A. places where ancient temples once rose that were commemorated with plaques detailing their history
B. a spiritual plane akin to the Catholic concept of purgatory where souls suffer punishments and await judgment
C. sites where Khmer Rouge militants exterminated Cambodians considered unfit for their new society
B. agricultural centers where large herds of livestock were shipped to be slaughtered and processed

C. sites where Khmer Rouge militants exterminated Cambodians considered unfit for their new society.