Why, in the Twentieth Century, Did Isolationist Foreign Policy Stances

Why, in the twentieth century, did isolationist foreign policy stances become less tenable or realistic in the United States?

A) Because the country's elites wanted to engage with the world and would not tolerate dissent
B) Solely due to the increased importance of foreign trade to the American economy
C) Because technological progress left the country less isolated from foreign threats, while global economic interdependence increased
D) Because technological progress left the country less isolated from foreign threats, while the federal government allowed foreign countries to hold its debt