Which of the diagrams correctly portrays the demand (D) and marginal revenue (MR) curves of a purely competitive seller?

The economic way of thinking assumes

A) people act selfishly. B) people act altruistically. C) people act to promote the projects in which they are interested. D) people do not act at all; they merely react to the environment around them.

Whenever the price of Good A decreases, the demand for Good B increases. Good A and B appear to be: a. complements. b. substitutes

c. inferior goods. d. normal goods.