Respuesta :
A reason the US adopted a policy of isolationism before World War II include the large number of American casualties in World War I. Therefore, here correct response is option B.
What was the reason of isolationism?
The main reason of isolationism was to avoid political or economic entanglements with the other countries.
Option 1 is incorrect because the Spanish Civil War didn't have American involvement and occurred in 1936 to 1939.
Option 3 is incorrect because that is not the definition of isolationism
Option 4 is incorrect because the desire to travel to foreign countries was not/is not a domestic policy issue.
Therefore, correct option is B.
Learn more about US policy, refer to the link:
https://brainly.com/question/1095626