Why was the iron curtain a problem?

The Iron Curtain represented the constant conflict and physical division between the Democrats and the Communists. This term was used to describe the conflict that existed from the end of World War II (1945) until the end of the Cold War in 1991. It is important to understand that the Iron Curtain was a concept used to describe the ideological division of Europe and did not physically exist. Although the Berlin wall was a very significant representation of the Iron Curtain, no one border or wall was the Iron Curtain.

The answer is c because i know the answer is c