Question

(Blank) took power in Cambodia immediately after the Vietnam War.

Answer 1

The Khmer Rouge took power in Cambodia immediately after the Vietnam War. I hope this helps :) 

Answer 2

The group that took power in Cambodia immediately after the vietnam war was:  a. the Khmer Rouge

The vietnam war was won by the northern vietnam, which means that communism become the dominant ideological force in Vietnam. This victory influence Cambodia (vietnam's neighboring country). The Khmer rouge also held a communism ideal similar to what is held by north vietnam.