challenge: What was the main change introduced by the Social Security Disability Benefits Reform Act of 1984 regarding the termination of benefits?
  
  A. Benefits could only be terminated if the individual's doctor recommended it
  B. Benefits could only be terminated if the individual was no longer a US citizen
  C. Benefits could be terminated without any specific conditions
  D. Benefits could only be terminated if the SSA demonstrated that the individual was capable of engaging in 'substantial gainful activity'
  Answer: 