Question

in response to the soviet unions invasion of afghanistan, the united states
○ ratified the salt ii treaty.
○ boycotted the 1980 summer olympics.
○ increased grain shipments to afghanistan.
○ stopped sending support to afghanistan.

Explanation:

In 1979, the Soviet Union invaded Afghanistan. As a major diplomatic and political response, the United States led a boycott of the 1980 Moscow Summer Olympics to protest this invasion. The SALT II Treaty was never ratified by the U.S. Senate; the U.S. halted grain shipments to the Soviet Union, not increased aid to Afghanistan, and later provided support to Afghan anti-Soviet forces, so the other options are incorrect.

Answer:

boycotted the 1980 Summer Olympics.