Final answer:
Reducing Social Security benefits is difficult due to the significant number of voters who depend on them for retirement income, making it politically sensitive and controversial. Option D.
Step-by-step explanation:
Attempts to reduce Social Security benefits prove to be difficult primarily due to the large voter base that supports them. Millions of retired Americans rely on Social Security as a vital source of income, notably after age 65.
These benefits are critical for the financial security of these individuals, many of whom count on Social Security for a substantial part of their retirement income. As such, any proposed reductions can be highly controversial and politically challenging.
Voters who benefit from or anticipate benefiting from Social Security have a significant influence on public policy, and politicians are wary of alienating this substantial and vocal constituency.
Moreover, given the current pay-as-you-go system, where the payments of current workers fund the benefits of retirees, changes can have immediate and long-lasting effects on the financial well-being of a vulnerable segment of the population.
So option D is correct.