The phrase the iron curtain is associated with what era of history?

The phrase iron curtain was used at different times in different contexts. originally it refers to the safety curtains deployed in theaters. But it became more famous in the cold war era when it was used to denote the economic, political and military barrier by the Soviet Union to block itself and its allied nations from the open contact with the western European countries. It virtually divided Europe into two areas of influence with western European countries on the one end and pro-communist eastern European countries on the other.

its c

the answer would be a i think?