Answer:
They faced both danger abroad and criticism at home.
Step-by-step explanation:
The involvement of the United States in the Vietnam War began in the year 1954 when the nation of Vietnam was divided between two parties who wanted to make a unified nation of communism on one side and another side wanting western influence and a bit more democratic. This resulted in the US being a part of the fight to ensure communism doesn't rule the nation.
American veterans faced a lot of pressure during and after the war. Not only do they have to ensure their survival during the war away from their homes, but their lives were also constantly in danger every second. And after the war, the war did not end. They felt isolated and neglected, unaccepted by the community which they defended. the criticism of being Vietnam War veterans and their involvement was criticized by a lot of people, making it even more difficult to blend with their own people/ community/ society.
Thus, the correct answer is the third option.