What was a major reason the soviet union
established satellite states in eastern europe
after world war ii?
(1) developing better trade relations with the
west
(2) creating a buffer zone against future invasions
(3) participating in united nations peacekeeping
missions
(4) controlling the organization of petroleum
exporting countries (opec)

A major reason why the Soviet Union did actually create satellite states following World War II in Eastern Europe was because they wanted to create a buffer zone against future invasions (2). 

The correct answer therefore is 2. 

They did this because they actually thought that war with the West was possible. For that reason, having buffer states between themselves and between a possible Western invasion, would help them in their cause.