In Figure 1.3, A, B, and C, which depicts the existence of opportunity cost? 

The aggregate production function shows that an economy increases its real GDP in the short run by

A) developing new technologies. B) increasing its physical capital stock. C) using more labor. D) exploring for new deposits of natural resources.

Sales taxes are routinely collected by

A) the merchants selling the good or services. B) the Internal Revenue Service. C) the Department of Commerce. D) the Federal Trade Commission.