Choice "C" is correct. Unemployment only tallies workers actively seeking employment; it does not count retirees or stay-at-home parents.
Choice "d" is incorrect. Frictional unemployment describes workers who leave work voluntarily to seek a better position.
Choice "a" is incorrect. Structural unemployment describes workers whose skills are no longer needed.
Choice "b" is incorrect. Cyclical unemployment describes workers unemployed due to the business cycle.
