Answer:
Eastern Bloc was the name that the NATO and the Western Europe used to call the Eastern European nations that was occupied and subsequently fell under the Soviet Union's hegemony.
However, the term Eastern Bloc was used to collectively call any Communist nation afterwards. But when the term Eastern bloc is used, it mainly meant the Eastern European nations.
Since you have not given any options, following are the Eastern European nations that were under the communist influence after the world war 2.
East Germany, Poland, Czechoslovakia, Hungary, Romania, Bulgaria, Yugoslavia and Albania
The Eastern bloc slowly disintegrated with fall of the communism in Easter Europe and eventually came to an end when the Soviet Union collapsed in 1991.
Explanation:
Following are some of the other communist countries from that era in other continents.
Mongolian People's Republic, the Socialist Republic of Vietnam, the Lao People's Democratic Republic and the People's Republic of Kampuchea, the Democratic People's Republic of Korea, and the People's Republic of China
Republic of Cuba
Are you asking what it is?
Because you can use every part of the animal
They were hindered by economic development and lack of enforcement, so I'd say 1. Cost, because no one would pay for it.