The soviet union ceased to exist in december 1991 due in part to a. gorbachev's reforms, leading to the end of the communist party. b. the boris yeltsin-led coup of the government c. the communists winning more seats than the reformers

The answer is B The Boris Yeltsin led coup of the government

The soviet union ceased to exist in 1991 due in part to : A. Gorbachev's reforms, leading to the end of the communist party

Gorbachev created a policy of "openness" and "restructuring"  which is the complete opposite of how the Soviet Union previously run the country. He removed the constitutional role of the communist party which eventually led to the ceasing of Soviet Union

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Because he proposed that all the treaties should be made through the league of nations.