Differing productivities, differences in working conditions, and localized employer market power are some of the reasons which explain differences in individual wages

The marginal cost curve:

a. Usually declines initially as output increases and then rises with further increases in output b. Is equal to the average variable cost curve c. Usually rises initially as output increases and declines with further increases in output d. Is always constant

Some economists argue that monopolistically competitive markets are inefficient because:

A. the firms earn economic profits in the long run. B. the firms' marginal costs and marginal revenues are not always equal. C. firms do not produce the output rate that would minimize their average total cost. D. barriers to entry are high.