- Perestroika (meaning "restructuring") was a political and economic reform movement within the Communist Party of the Soviet Union, associated with Mikhail Gorbachev, implemented from 1985 onwards. - Statement A is true: Mikhail Gorbachev authored a book titled "Perestroika: New Thinking for Our Country and the World" explaining his reforms. - Statement B is true: Perestroika sought to reform the existing socialist system, not abolish it, and was critical of the centralized, authoritarian aspects associated with Stalin's rule (anti-Stalinist but not anti-socialist). - Statement D is true: Gorbachev often invoked the ideals of Lenin, particularly his New Economic Policy (NEP), to justify market-oriented reforms and decentralization as a return to true Leninist principles that had been distorted by later Soviet leaders. - Statement C is false: Perestroika was a policy aimed at reforming the Soviet Union itself. The Commonwealth of Independent States (CIS) was formed in December 1991 after the dissolution of the Soviet Union, a process that the failure of Perestroika to revitalize the USSR arguably accelerated. Perestroika did not aim to create the CIS; the CIS emerged as a successor entity after the USSR collapsed.