Question

an official government order that limits trade with another nation to punish or pressure that nation in some way is known as
an act of war.
an embargo.
isolationism.
appeasement.

Explanation:

An embargo is a government - imposed restriction on trade with another nation as a form of punishment or pressure. An act of war is a military action, isolationism is a foreign - policy stance of staying out of foreign affairs overall, and appeasement is the policy of making concessions to an aggressive power to avoid conflict.

Answer:

B. an embargo