Referring to Table 4.2, Box R should be filled with 

Economist George Borjas has estimated the net benefits (+)/costs (-) to the United States from labor immigration to be approximately:

a. +10% of GDP. b. -5% of GDP. c. +0.1% of GDP. d. 0.5% capital loses and 0.8% labor gains.

Taxes can be justified if the government uses the revenue to (i) provide public goods such as national defense. (ii) clean up negative externalities such as water pollution. (iii) regulate a common resource such as fish in a public lake. (iv) provide goods with positive externalities such as medical research

a. (ii) only b. (ii) and (iii) only c. (i), (ii), and (iii) only d. (i), (ii), (iii), and (iv)