Assume both the marginal cost and the average variable cost curves are U-shaped. At the minimum point on the AVC curve, marginal cost must be:

A decline in the minimum wage rate offered for janitorial services will cause: a. the labor supply curve to shift rightward

b. the labor supply curve to shift leftward. c. a downward movement along the labor supply curve. d. an upward movement along the labor supply curve.

According to the No Marginal Improvement Principle, if X* is the best choice, then:

A. MB must be greater than MC at X*. B. MB must be equal to MC at X*. C. MB must be less than MC at X*. D. MB must be greater than or equal to MC at X*.