The appropriate answer in A. Building the Berlin Wall. The official purpose of the Berlin Wall was to prevent West Germany from undermining the political ideals from East Germany. The Wall also prevent East Germans from going to the West.
Construction of the wall began in 1961 and was used until it's 'fall' on November 9, 1989. The wall was initially concrete and barbed wire but was fortified over time with various check points to monitor traffic.
