Most Soviet Union client states in Eastern Europe were ruled by

1.) Democratic governments allied with the Soviet Union

2.) Communist governments under Soviet control

3.) The Soviet military

communist governments under Soviet control

The correct answer is - 2.) Communist governments under Soviet control.

The Soviet Union, just like the United States, during the Cold War period tried to have as many allies as possible in order to have stronger support and protect its interests. Eastern Europe was a region that was almost totally under the control of the Soviets, apart from Yugoslavia which was strong on its own and didn't wanted to be submissive to other country.

The Soviets sponsored Communist governments and gave them a lot of support, be it financial, propaganda, or even military one if there were problems in the country. That led to almost all of the Eastern European nations having governments that were under the influence and control of the Soviets, making them a satellite countries to the Soviet Union.