Answer:
a. Isolationism and/or neutrality.
Step-by-step explanation:
Isolationist feelings have always been strong in the United States. People and many politicians have normally been reluctant to get the country engaged in foreign wars that were deemed as having nothing to do with American interests or benefit. This was a feeling that started to evolve with the Spanish-American War. When World War One broke out, the initial reaction was not to participate. But the sinking of the Lusitania - and the loss of 128 American lives - and the outrageous Zimmerman Telegram change the mood of the US public.