Refer to the diagram. At disposable income level D, the average propensity to save is equal to:

The above figure shows the demand curve for movie rentals from Redbox. At which of the following prices is the demand unit elastic?

A) $5.00 B) $3.50 C) $2.50 D) $0.00

As Sam moves rightward along his indifference curve, his marginal rate of substitution

A) is diminishing. B) is increasing. C) remains constant. D) shows the change in his income.