In which year Mikhail Gorbachev become General Secretary of the Communist party of the Soviet Union?

1985

The correct answer is Option (4) → 1985

Mikhail Gorbachev elected as the General Secretary of the Communist Party of the Soviet Union in 1985.

Mikhail Gorbachev (Born 1931): Last leader of the Soviet Union (1985- 91); introduced economic and political reform policies of perestroika (restructuring) and glasnost (openness); stopped the arms race with the US; withdrew Soviet troops from Afghanistan and eastern Europe; helped in the unification of Germany; ended the Cold War; blamed for the disintegration of the Soviet Union.