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 for punitive or pressurizing purposes. An act of war is an aggressive military action. Isolationism is a policy of staying out of foreign affairs in general. Appeasement is the policy of making concessions to an aggressive power to avoid conflict.

Answer:

B. an embargo