In the above figure, if the market produces the efficient amount of purses then producer surplus equals triangle

A product that has a negative income elasticity of demand is ________ good

A) a complementary B) a substitute C) a normal D) an inferior E) a negative

For an individual who consumes only two goods, x and y, the opportunity cost of consuming one more unit of x in terms of how much y must be given up is reflected by:

a. the individual's marginal rate of substitution. b. the market prices of x and y. c. the slope of the individual's indifference curve. d. none of the above.