Which of the following statements best defines the economics of the so-called superstar effect in the labor market? a. This effect occurs in cases in which individuals with small productivity differences receive very small differences in compensation. b. This effect usually occurs in industries in which a labor union has far-reaching powers. c. This effect occurs in cases in which individuals with small productivity differences receive vastly different compensation. d. This effect will result in cases in which individuals with large productivity differences receive vastly different compensation. e. This effect occurs when the firm hiring the superstar simply does not understand the term marginal-revenue product.