Refer to Figure 5-1. The efficient equilibrium quantity is ________ thousand vaccinations

When a society achieves allocative efficiency, it

A) is not achieving production efficiency. B) is producing that combination of goods and services that society values most highly. C) might or it might not be producing at a point on society's PPF. D) is producing a combination of goods and services whose marginal cost exceeds their marginal benefit. E) is producing the combination of goods and services for which marginal benefit exceeds marginal cost by as much as possible.

In perfect competition, the product of a single firm

A) has many perfect substitutes produced by other firms. B) has many perfect complements produced by other firms. C) is sold under many differing brand names. D) is sold to different customers at different prices.