Which of the following statements about efficiency wage theory is true ?

• A. Paying above the competitive equilibrium wage tends to cause workers to shirk their responsibilities
• B. Firms do not have a choice about whether they pay efficiency wages or not because these wages are determined by law
• C. Paying the lowest possible wage is always the most efficient (Profitable)
• D. Paying above the competitive equilibrium wage may improve worker health lower worker turnover improve worker quality and increase worker effort