An expansionary fiscal policy will be effective only if the central bank of a country simultaneously prevents the market interest rate from rising

Which of the following statements is true?

A) A rational consumer makes his decisions depending on what the majority chooses. B) A trade-off refers to the exchange of goods between economic agents through a barter system or mutual exchange. C) A budget constraint is an economic tool that quantifies the trade-off between consumption of two goods. D) All rational economic agents attempt to maximize their income.

If external costs are included and added to a firm's private costs, then

A) the demand curve will shift to the right. B) the demand curve will shift to the left. C) the supply curve will shift to the right. D) the supply curve will shift to the left.