In 1981, a bipartisan National Commission on Social Security Reform made several recommendations ...

In 1981, a bipartisan National Commission on Social Security Reform
  made several recommendations which would lead to long-term
  solvency of the social insurance system. Which of the following
  recommendations was eventually adopted?
 
  A. requiring workers born after 1980 to participate in private
  pension plans instead of Social Security
  B. removing workers who earned an annual income of over
  250,000 from receiving Social Security
  C. gradually increasing the retirement age for full benefits to 67
  D. changing Social Security to an optional, means-tested program