What was the soviet union’s primary purpose in building the berlin wall?

To stop it's people from leaving.

Explanation:

East Germany, DDR (Deutsche Demokratische Republik) put up the wall to stop it's people from leaving. At first there was no real wall or barrier stopping any Wessi oder Ossi from coming into each others country. To skip the complex stuff. People began seeing the future of their country if they stayed in the East, meaning people began to leave and not come back.. So, what's a country with no people? So the wall was put up not only to keep it's people in, but also to keep people out, but mostly in

the correct answer is b.