U.S. export spending is not affected by U.S. real income but is influenced by the economic activity of its major trading partners and the exchange rate, hence export spending is taken as autonomous

The figure above shows the demand and marginal revenue curves facing Sue's Surfboards, the sole renter of surfboards on Big Wave Island. If Sue is renting 25 surfboards an hour so that the marginal revenue is negative, then Sue's Surfboards

A) can increase its profit by increasing the number of rentals. B) must face an inelastic demand for surfboard rentals. C) must face a unit elastic demand for surfboard rentals. D) must face an elastic demand for surfboard rentals.

Which of the following will not cause a movement along the supply curve?

a. Changes in the sellers' expectations. b. Increases in taxes per unit of output. c. Advances in technology. d. All of these.