What frustrated Shishatsky the most when the Soviet were in charge

Explanation:

According to Shishatsky, he feels regret for those who are nostalgic for "the good old Soviet days" when all the Soviet people were "brothers and sisters" and unanimously supported the Communist Party, which did everything possible day and night to achieve well-being of the entire Soviet nation. Most of these people are elderly, in their sixties and seventies. They are pensioners, veterans of World War II (who had many privileges in Soviet times), and many ordinary people who are alone and frustrated.

People believed in a better "bright future", but they didn't win anything.

d is the logical answer but im not a 100% sure