Gorbachev advocated changes to make the system work more effitiently. he called for perestroika which means

policy restructuring

Explanation:

(in the former Soviet Union) the policy or practice of restructuring or reforming the economic and political system. First proposed by Leonid Brezhnev in 1979 and actively promoted by Mikhail Gorbachev, perestroika originally referred to increased automation and labour efficiency, but came to entail greater awareness of economic markets and the ending of central planning

i am not 100   percent sure but i do know that hitler was burned to death with gas so that makes me think it is d. because they were under his control if they fail or not do as told they will be killed but i could be wrong hope this