Social Security, fraud, and Ponzi schemes

Recent, useful essays from Jacob Sullum and John Stossel on Social Security...

The claim that "Social Security = Ponzi scheme" is:
a.) too rough on SS, since "scheme" implies intent

b.) too light on SS, since it's mandatory and causes so much pain for the working poor and middle class

c.) too rough on SS, since the former is legal

d.) too light on SS, since both are immoral and the former has the sanction of the governing authority

e.) too rough on SS, since the latter is built on fraud

f.) too light on SS, since the former is supported by fraud and takes advantage of trusting citizens