The correct answer is 2. Isolationism
Following world war 1, United States didn't want to mess with European affairs because they understood how bad the war was and didn't want to participate in it again. That's why when Wilson wanted to join the League of Nations they declined and the US remained on its own.
The goal was for <span>The supervision of war-related industries to make sure businesses were not profiteering</span>
They attacked only at night under the cover of darkness. Their tactic was to engage in small skirmishes in the South Vietnamese countryside where they were familiar with the area. They used guerilla warfare and had their trip wires and pits with sharpened bamboo stakes to demobilize the enemy. After the battle, they escaped back to the jungle.