What tactics did stalin use to take control in eastern europe?

This answer is a bit long...but a lot has to be said to understand

As a result of the victory in the Great Patriotic War/ WW2, Soviet troops were on the territory of the liberated countries of Eastern Europe. Here the formation of new authorities immediately began. The governments of Eastern European states, in which local communists and their allies played a prominent role, began to focus on Moscow. Leading positions in the Communist parties, with rare exceptions, were occupied by politicians who passed through the school of the Comintern. The strong influence of left-wing political forces in Eastern Europe was due to their active participation in the resistance movement, the weakening of right-wing forces after the defeat of fascism, and the frank support of the Soviet Union. At first, the communist parties were, as a rule, part of broad socio-political association. Communist Party representatives received ministerial portfolios in coalition governments. Gradually their influence increased. In particular, the authority of the Communists grew after the agrarian reform in Eastern European countries, accompanied by the destruction of large land tenure. Now the support of the Communist Party began to be received from the peasants. By the end of the 40s. Communists ousted representatives of other parties from the governments, establishing their control over the states of Eastern Europe. Almost everywhere, the seizure of power by the Communist parties was carried out without armed violence, with the visible preservation of democratic procedures. In the postwar years, the East European socialist countries have achieved significant success. With the active assistance of the USSR, their economic potential was restored. If before the war only Czechoslovakia had developed industry, then in the second half of the 20th century, modern industry was created in all of Eastern European countries. Even such traditionally agrarian countries as Bulgaria and Romania confidently embarked on the path of industrial development.

all choices are correct