In this graph for the marginal costs and benefits of pollution controls, investing more capital and labor to reduce pollution is efficient at ______.

In the above table, saving must be

A) -$300 billion. B) $300 billion. C) $400 billion. D) -$400 billion.

Marginal utility theory predicts that a rise in the price of a banana results in

A) the demand curve for bananas shifting rightward. B) the demand curve for bananas shifting leftward. C) a movement upward along the demand curve for bananas. D) a movement downward along the demand curve for bananas.