Answer:
The development of government is a recent development in human history
"President Nixon believed his Vietnamization strategy, which involved building up South Vietnam's armed forces and withdrawing U.S.troops, would prepare the SouthVietnamese to act in their own defense against a North Vietnamese takeover and allow the United States to leave Vietnam with its honor intact." -Google
"Henry Kissinger signs the Paris Peace Accords on Jan. 27, 1973 in Paris. The war ended on April 30, 1975, when Saigon surrendered almost without fighting to the communist forces, ending the United States’ involvement in Vietnam.*" - https://slate.com/human-interest/2014/11/why-did-america-lose-the-vietnam-war.html
Answer: A- A system with three distinct branches of government :)
