Efficiency wages are: a above-market-wages that bring forth so much added work effort that per-unit production costs are lower than at market wages. b wage payments necessary to compensate workers for unpleasant or risky work conditions. c usually less than market wages. d relevant to macro economics because they explain rightward shifts in aggregate demand.

Efficiency wages are the wages that are above market wages that brings more added work effort where per unit production costs are lower than at market wages(A)

Explanation:

The efficiency wage hypothesis states that the wages, in some labour markets, are formed in a way which is not market clearing.

Efficiency wage points to the fact that managers pay their workers more than the market clearing wage to increase their efficiency or productivity and reduce the costs that is associated with employee turnover especially in the industries where there is high costs of replacing labor. The increase in labor productivity and the decrease in costs results into the higher wages paid to the employees.

answer; is the sum of all individual demands curves;