The correct options are a, b, c, and d.
Joseph Stalin maintained a strong dictatorship in the Soviet Union through various means, including the reorganization of the economy through five-year plans to industrialize the country, the ruthless elimination of political and social opponents through purges, and the use of secret police and the gulag system to instill fear in the people and suppress dissent. Stalin's regime was known for its extreme brutality and disregard for human life, and he was responsible for the deaths of millions of people.
Option e is incorrect because Stalin did not allow all religions to practice freely in Soviet Russia. In fact, he actively persecuted religious groups, particularly the Russian Orthodox Church, which he viewed as a threat to his power.