The supply curve for land is vertical.

Along a linear demand curve,

a. both the slope and price elasticity are constant b. the price elasticity is constant, but the slope varies c. total revenues are constant d. the slope is constant, but the price elasticity varies e. total revenues are negative

In 2007 a company sold 35,000 drones at $150 each. In 2008 the same company sold 40,000 drones at $170 each. This information suggests that

A. The price of drones increased because the costs of production increased from 2007 to 2008. B. From 2007 to 2008, the demand curve for drones was upward-sloping because of improved technology. C. The supply of drones increased from 2007 to 2008. D. The demand for drones increased from 2007 to 2008.