Which of the Following Is an Example of Unilateralism in American

Which of the following is an example of unilateralism in American foreign policy?

A) participation by the U.S. in organized sanctions to stop North Korea's nuclear program
B) President Obama's approach to foreign affairs
C) the U.S. refusal to sign treaties establishing an international criminal court
D) U.S. leadership of and financial contributions to the IMF and World Bank
E) the U.S. agreement to suspend normal trade rules and allow global firms to produce critical generic drugs